Change Unit.multiplier type from decimal to float

Remove remnants related to BigDecimal.
Improve Units tests and remove test parallelization
2026-05-23 17:02:01 +02:00 · 2026-05-15 00:21:10 +02:00 · 2026-05-15 00:21:01 +02:00 · 2026-05-15 00:20:28 +02:00 · 2026-05-07 20:53:18 +02:00 · 2026-05-07 18:20:06 +02:00
78 changed files with 1460 additions and 1062 deletions
--- a/.gitea/workflows/test.yml
+++ b/.gitea/workflows/test.yml
@@ -1,74 +0,0 @@
-name: Tests
-
-on:
-  push:
-    branches: [ master ]
-  pull_request:
-    branches: [ master ]
-
-jobs:
-  test-sqlite:
-    name: Tests (SQLite)
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-
-      - uses: ruby/setup-ruby@v1
-        with:
-          ruby-version: '3.3'
-          bundler-cache: true
-        env:
-          BUNDLE_WITH: "sqlite:development:test"
-
-      - name: Set up test database
-        run: bin/rails db:create db:schema:load
-        env:
-          RAILS_ENV: test
-
-      - name: Run tests
-        run: bin/rails test
-        env:
-          RAILS_ENV: test
-          CI: "true"
-
-  test-mysql:
-    name: Tests (MySQL)
-    runs-on: ubuntu-latest
-
-    services:
-      mysql:
-        image: mysql:8.0
-        env:
-          MYSQL_ROOT_PASSWORD: ""
-          MYSQL_ALLOW_EMPTY_PASSWORD: "yes"
-          MYSQL_DATABASE: fixin_test
-        ports:
-          - 3306:3306
-        options: >-
-          --health-cmd="mysqladmin ping"
-          --health-interval=10s
-          --health-timeout=5s
-          --health-retries=3
-
-    steps:
-      - uses: actions/checkout@v4
-
-      - uses: ruby/setup-ruby@v1
-        with:
-          ruby-version: '3.3'
-          bundler-cache: true
-        env:
-          BUNDLE_WITH: "mysql:development:test"
-
-      - name: Set up test database
-        run: bin/rails db:schema:load
-        env:
-          RAILS_ENV: test
-          DB_ADAPTER: mysql
-
-      - name: Run tests
-        run: bin/rails test
-        env:
-          RAILS_ENV: test
-          CI: "true"
-          DB_ADAPTER: mysql
--- a/.gitignore
+++ b/.gitignore
@@ -15,6 +15,9 @@
 /config/master.key
 /config/puma.rb

+# Ignore test database.
+/db/test.sqlite3
+
 # Ignore all logfiles and tempfiles.
 /log/*
 /tmp/*
@@ -30,7 +33,7 @@

 /tmp/restart.txt

-# Ignore user files
+# Ignore user files.
 /.bash_history
 /.byebug_history
 /.config
@@ -38,6 +41,7 @@
 /.lesshst
 /.local
 /.mysql_history
+/.sqlite_history
 /.ssh
 /.vim
 /.viminfo
--- a/DESIGN.md
+++ b/DESIGN.md
@@ -0,0 +1,59 @@
+DESIGN
+======
+
+Below is a list of design decisions. The justification is to be consulted
+whenever a change is considered, to avoid regressions.
+
+### Data type for DB storage of numeric values (`decimal` vs `float`)
+
+* among database engines supported (by Rails), SQLite offers storage of
+  `decimal` data type with the lowest precision, equal to the precision of
+  `REAL` type (double precision float value, IEEE 754), but in a floating point
+  format,
+    * decimal types in other database engines offer greater precision, but store
+      data in a fixed point format,
+* biology-related values differ by several orders of magnitude; storing them in
+  fixed point format would only make sense if required precision would be
+  greater than that offered by floating point format,
+    * even then, fixed point would mean either bigger memory requirements or
+      worse precision for numbers close to scale limit,
+        * for a fixed point format to use the same 8 bytes of storage as IEEE
+          754, precision would need to be limited to 18 digits (4 bytes/9 digits)
+          and scale approximately half of that - 9,
+    * double precision floating point guarantees 15 digits of precision, which
+      is more than enough for all expected use cases,
+        * if a decimal string with at most 15 significant digits is converted to
+          the IEEE 754 double-precision format, giving a normal number, and then
+          converted back to a decimal string with the same number of digits, the
+          final result should match the original string,
+        * if an IEEE 754 double-precision number is converted to a decimal
+          string with at least 17 significant digits, and then converted back to
+          double-precision representation, the final result must match the
+          original number,
+        * single precision floating point only guarntees 6 digits of precision,
+          which is estimated to be too low for some use cases (e.g. storing
+          latitude/longitude with a resolution grater than 100m),
+* double precision floating point (IEEE 754) is a standard that ensures
+  compatibility with majority of database engines,
+    * the same data format is used internally by Ruby as a `Float`; it
+      guarantees no conversions between storage and computation,
+    * as a standard with hardware implementations ensures both: computing
+      efficiency and hardware/3rd party library compatibility as opposed to Ruby
+      custom `BigDecimal` type,
+    * at present, only normalized numbers are used and considered sufficient, in
+      order to avoid potential issues with the cross-platform compatibility of
+      subnormal (denormal) numbers,
+* in the future, the IEEE 754 decimal64 data type may be considered once it is
+  supported by database engines.
+
+### Database layer vs application layer data model constraints
+
+* database constraints are the final guard against data integrity corruption,
+    * they should safeguard against data referential integrity loss under _all_
+      data (not schema) manipulation scenarios, including application level
+      logic errors and direct data manipulation (e.g. through `dbconsole`),
+* application constraints can be as restrictive as database constraints or more,
+  but not less, as it doesn't serve any use case,
+    * proper application level constraints should prevent unhandled database
+      exception occurences, e.g `ActiveRecord::InvalidForeignKey` for operations
+      performed through Models (i.e. not `#delete_all` etc.)
--- a/15
+++ b/15
@@ -1,14 +1,18 @@
 source "https://rubygems.org"

 # The requirement for the Ruby version comes from Rails
-gem "rails", "~> 7.2.3"
+# NOTE: after updating Rails make sure that schema dump is not sorted:
+#   v8.1.3/activerecord/lib/active_record/schema_dumper.rb#L195
+# Waiting for this change to be reverted/configuration setting added:
+# https://github.com/rails/rails/pull/56842, https://github.com/rails/rails/pull/55414
+gem "rails", "~> 8.1.3"
 gem "sprockets-rails"
 gem "puma", "~> 6.0"
 gem "sassc-rails"
 # Windows does not include zoneinfo files, so bundle the tzinfo-data gem
 gem "tzinfo-data", platforms: %i[ mingw mswin x64_mingw jruby ]

-# TODO: select db gems automatically
+# TODO: select db gems automatically?
 #   database_config = ERB.new(File.read("config/database.yml")).result
 #   YAML.load(database_config, aliases: true).values.map { |env| env["adapter"] }.uniq
 group :mysql, optional: true do
@@ -42,11 +46,4 @@ group :test do
  # Use system testing [https://guides.rubyonrails.org/testing.html#system-testing]
  gem "capybara"
  gem "selenium-webdriver"
-
-  # Remove minitest version restriction after error fixed:
-  #   railties-7.2.3/lib/rails/test_unit/line_filtering.rb:7:in `run':
-  #     wrong number of arguments (given 3, expected 1..2) (ArgumentError)
-  #   from /var/www/.gem/ruby/3.3.0/gems/minitest-6.0.2/lib/minitest.rb:473:in
-  #     `block (2 levels) in run_suite'
-  gem "minitest", "< 6"
 end
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,85 +1,85 @@
 GEM
  remote: https://rubygems.org/
  specs:
-    actioncable (7.2.3)
-      actionpack (= 7.2.3)
-      activesupport (= 7.2.3)
+    action_text-trix (2.1.18)
+      railties
+    actioncable (8.1.3)
+      actionpack (= 8.1.3)
+      activesupport (= 8.1.3)
      nio4r (~> 2.0)
      websocket-driver (>= 0.6.1)
      zeitwerk (~> 2.6)
-    actionmailbox (7.2.3)
-      actionpack (= 7.2.3)
-      activejob (= 7.2.3)
-      activerecord (= 7.2.3)
-      activestorage (= 7.2.3)
-      activesupport (= 7.2.3)
+    actionmailbox (8.1.3)
+      actionpack (= 8.1.3)
+      activejob (= 8.1.3)
+      activerecord (= 8.1.3)
+      activestorage (= 8.1.3)
+      activesupport (= 8.1.3)
      mail (>= 2.8.0)
-    actionmailer (7.2.3)
-      actionpack (= 7.2.3)
-      actionview (= 7.2.3)
-      activejob (= 7.2.3)
-      activesupport (= 7.2.3)
+    actionmailer (8.1.3)
+      actionpack (= 8.1.3)
+      actionview (= 8.1.3)
+      activejob (= 8.1.3)
+      activesupport (= 8.1.3)
      mail (>= 2.8.0)
      rails-dom-testing (~> 2.2)
-    actionpack (7.2.3)
-      actionview (= 7.2.3)
-      activesupport (= 7.2.3)
-      cgi
+    actionpack (8.1.3)
+      actionview (= 8.1.3)
+      activesupport (= 8.1.3)
      nokogiri (>= 1.8.5)
-      racc
-      rack (>= 2.2.4, < 3.3)
+      rack (>= 2.2.4)
      rack-session (>= 1.0.1)
      rack-test (>= 0.6.3)
      rails-dom-testing (~> 2.2)
      rails-html-sanitizer (~> 1.6)
      useragent (~> 0.16)
-    actiontext (7.2.3)
-      actionpack (= 7.2.3)
-      activerecord (= 7.2.3)
-      activestorage (= 7.2.3)
-      activesupport (= 7.2.3)
+    actiontext (8.1.3)
+      action_text-trix (~> 2.1.15)
+      actionpack (= 8.1.3)
+      activerecord (= 8.1.3)
+      activestorage (= 8.1.3)
+      activesupport (= 8.1.3)
      globalid (>= 0.6.0)
      nokogiri (>= 1.8.5)
-    actionview (7.2.3)
-      activesupport (= 7.2.3)
+    actionview (8.1.3)
+      activesupport (= 8.1.3)
      builder (~> 3.1)
-      cgi
      erubi (~> 1.11)
      rails-dom-testing (~> 2.2)
      rails-html-sanitizer (~> 1.6)
-    activejob (7.2.3)
-      activesupport (= 7.2.3)
+    activejob (8.1.3)
+      activesupport (= 8.1.3)
      globalid (>= 0.3.6)
-    activemodel (7.2.3)
-      activesupport (= 7.2.3)
-    activerecord (7.2.3)
-      activemodel (= 7.2.3)
-      activesupport (= 7.2.3)
+    activemodel (8.1.3)
+      activesupport (= 8.1.3)
+    activerecord (8.1.3)
+      activemodel (= 8.1.3)
+      activesupport (= 8.1.3)
      timeout (>= 0.4.0)
-    activestorage (7.2.3)
-      actionpack (= 7.2.3)
-      activejob (= 7.2.3)
-      activerecord (= 7.2.3)
-      activesupport (= 7.2.3)
+    activestorage (8.1.3)
+      actionpack (= 8.1.3)
+      activejob (= 8.1.3)
+      activerecord (= 8.1.3)
+      activesupport (= 8.1.3)
      marcel (~> 1.0)
-    activesupport (7.2.3)
+    activesupport (8.1.3)
      base64
-      benchmark (>= 0.3)
      bigdecimal
      concurrent-ruby (~> 1.0, >= 1.3.1)
      connection_pool (>= 2.2.5)
      drb
      i18n (>= 1.6, < 2)
+      json
      logger (>= 1.4.2)
      minitest (>= 5.1)
      securerandom (>= 0.3)
      tzinfo (~> 2.0, >= 2.0.5)
-    addressable (2.8.8)
+      uri (>= 0.13.1)
+    addressable (2.9.0)
      public_suffix (>= 2.0.2, < 8.0)
    base64 (0.3.0)
-    bcrypt (3.1.21)
-    benchmark (0.5.0)
-    bigdecimal (4.0.1)
+    bcrypt (3.1.22)
+    bigdecimal (4.1.2)
    bindex (0.8.1)
    builder (3.3.0)
    byebug (13.0.0)
@@ -93,28 +93,27 @@ GEM
      rack-test (>= 0.6.3)
      regexp_parser (>= 1.5, < 3.0)
      xpath (~> 3.2)
-    cgi (0.5.1)
    concurrent-ruby (1.3.6)
    connection_pool (3.0.2)
    crass (1.0.6)
    date (3.5.1)
-    devise (5.0.2)
+    devise (5.0.3)
      bcrypt (~> 3.0)
      orm_adapter (~> 0.1)
      railties (>= 7.0)
      responders
      warden (~> 1.2.3)
    drb (2.2.3)
-    erb (6.0.2)
+    erb (6.0.4)
    erubi (1.13.1)
-    ffi (1.17.3-aarch64-linux-gnu)
-    ffi (1.17.3-aarch64-linux-musl)
-    ffi (1.17.3-arm-linux-gnu)
-    ffi (1.17.3-arm-linux-musl)
-    ffi (1.17.3-arm64-darwin)
-    ffi (1.17.3-x86_64-darwin)
-    ffi (1.17.3-x86_64-linux-gnu)
-    ffi (1.17.3-x86_64-linux-musl)
+    ffi (1.17.4-aarch64-linux-gnu)
+    ffi (1.17.4-aarch64-linux-musl)
+    ffi (1.17.4-arm-linux-gnu)
+    ffi (1.17.4-arm-linux-musl)
+    ffi (1.17.4-arm64-darwin)
+    ffi (1.17.4-x86_64-darwin)
+    ffi (1.17.4-x86_64-linux-gnu)
+    ffi (1.17.4-x86_64-linux-musl)
    globalid (1.3.0)
      activesupport (>= 6.1)
    i18n (1.14.8)
@@ -124,13 +123,14 @@ GEM
      activesupport (>= 6.0.0)
      railties (>= 6.0.0)
    io-console (0.8.2)
-    irb (1.17.0)
+    irb (1.18.0)
      pp (>= 0.6.0)
      prism (>= 1.3.0)
      rdoc (>= 4.0.0)
      reline (>= 0.4.2)
+    json (2.19.4)
    logger (1.7.0)
-    loofah (2.25.0)
+    loofah (2.25.1)
      crass (~> 1.0.2)
      nokogiri (>= 1.12.0)
    mail (2.9.0)
@@ -142,10 +142,12 @@ GEM
    marcel (1.1.0)
    matrix (0.4.3)
    mini_mime (1.1.5)
-    minitest (5.27.0)
+    minitest (6.0.6)
+      drb (~> 2.0)
+      prism (~> 1.5)
    mysql2 (0.5.7)
      bigdecimal
-    net-imap (0.6.3)
+    net-imap (0.6.4)
      date
      net-protocol
    net-pop (0.1.2)
@@ -155,21 +157,21 @@ GEM
    net-smtp (0.5.1)
      net-protocol
    nio4r (2.7.5)
-    nokogiri (1.19.1-aarch64-linux-gnu)
+    nokogiri (1.19.3-aarch64-linux-gnu)
      racc (~> 1.4)
-    nokogiri (1.19.1-aarch64-linux-musl)
+    nokogiri (1.19.3-aarch64-linux-musl)
      racc (~> 1.4)
-    nokogiri (1.19.1-arm-linux-gnu)
+    nokogiri (1.19.3-arm-linux-gnu)
      racc (~> 1.4)
-    nokogiri (1.19.1-arm-linux-musl)
+    nokogiri (1.19.3-arm-linux-musl)
      racc (~> 1.4)
-    nokogiri (1.19.1-arm64-darwin)
+    nokogiri (1.19.3-arm64-darwin)
      racc (~> 1.4)
-    nokogiri (1.19.1-x86_64-darwin)
+    nokogiri (1.19.3-x86_64-darwin)
      racc (~> 1.4)
-    nokogiri (1.19.1-x86_64-linux-gnu)
+    nokogiri (1.19.3-x86_64-linux-gnu)
      racc (~> 1.4)
-    nokogiri (1.19.1-x86_64-linux-musl)
+    nokogiri (1.19.3-x86_64-linux-musl)
      racc (~> 1.4)
    orm_adapter (0.5.0)
    pg (1.6.3)
@@ -186,32 +188,32 @@ GEM
    psych (5.3.1)
      date
      stringio
-    public_suffix (7.0.2)
+    public_suffix (7.0.5)
    puma (6.6.1)
      nio4r (~> 2.0)
    racc (1.8.1)
-    rack (3.2.5)
-    rack-session (2.1.1)
+    rack (3.2.6)
+    rack-session (2.1.2)
      base64 (>= 0.1.0)
      rack (>= 3.0.0)
    rack-test (2.2.0)
      rack (>= 1.3)
    rackup (2.3.1)
      rack (>= 3)
-    rails (7.2.3)
-      actioncable (= 7.2.3)
-      actionmailbox (= 7.2.3)
-      actionmailer (= 7.2.3)
-      actionpack (= 7.2.3)
-      actiontext (= 7.2.3)
-      actionview (= 7.2.3)
-      activejob (= 7.2.3)
-      activemodel (= 7.2.3)
-      activerecord (= 7.2.3)
-      activestorage (= 7.2.3)
-      activesupport (= 7.2.3)
+    rails (8.1.3)
+      actioncable (= 8.1.3)
+      actionmailbox (= 8.1.3)
+      actionmailer (= 8.1.3)
+      actionpack (= 8.1.3)
+      actiontext (= 8.1.3)
+      actionview (= 8.1.3)
+      activejob (= 8.1.3)
+      activemodel (= 8.1.3)
+      activerecord (= 8.1.3)
+      activestorage (= 8.1.3)
+      activesupport (= 8.1.3)
      bundler (>= 1.15.0)
-      railties (= 7.2.3)
+      railties (= 8.1.3)
    rails-dom-testing (2.3.0)
      activesupport (>= 5.0.0)
      minitest
@@ -219,29 +221,28 @@ GEM
    rails-html-sanitizer (1.7.0)
      loofah (~> 2.25)
      nokogiri (>= 1.15.7, != 1.16.7, != 1.16.6, != 1.16.5, != 1.16.4, != 1.16.3, != 1.16.2, != 1.16.1, != 1.16.0.rc1, != 1.16.0)
-    railties (7.2.3)
-      actionpack (= 7.2.3)
-      activesupport (= 7.2.3)
-      cgi
+    railties (8.1.3)
+      actionpack (= 8.1.3)
+      activesupport (= 8.1.3)
      irb (~> 1.13)
      rackup (>= 1.0.0)
      rake (>= 12.2)
      thor (~> 1.0, >= 1.2.2)
      tsort (>= 0.2)
      zeitwerk (~> 2.6)
-    rake (13.3.1)
+    rake (13.4.2)
    rdoc (7.2.0)
      erb
      psych (>= 4.0.0)
      tsort
-    regexp_parser (2.11.3)
+    regexp_parser (2.12.0)
    reline (0.6.3)
      io-console (~> 0.5)
    responders (3.2.0)
      actionpack (>= 7.0)
      railties (>= 7.0)
    rexml (3.4.4)
-    rubyzip (3.2.2)
+    rubyzip (3.3.0)
    sassc (2.4.0)
      ffi (~> 1.9)
    sassc-rails (2.1.2)
@@ -251,7 +252,7 @@ GEM
      sprockets-rails
      tilt
    securerandom (0.4.1)
-    selenium-webdriver (4.41.0)
+    selenium-webdriver (4.43.0)
      base64 (~> 0.2)
      logger (~> 1.4)
      rexml (~> 3.2, >= 3.2.5)
@@ -265,32 +266,32 @@ GEM
      actionpack (>= 6.1)
      activesupport (>= 6.1)
      sprockets (>= 3.0.0)
-    sqlite3 (2.9.0-aarch64-linux-gnu)
-    sqlite3 (2.9.0-aarch64-linux-musl)
-    sqlite3 (2.9.0-arm-linux-gnu)
-    sqlite3 (2.9.0-arm-linux-musl)
-    sqlite3 (2.9.0-arm64-darwin)
-    sqlite3 (2.9.0-x86_64-darwin)
-    sqlite3 (2.9.0-x86_64-linux-gnu)
-    sqlite3 (2.9.0-x86_64-linux-musl)
+    sqlite3 (2.9.3-aarch64-linux-gnu)
+    sqlite3 (2.9.3-aarch64-linux-musl)
+    sqlite3 (2.9.3-arm-linux-gnu)
+    sqlite3 (2.9.3-arm-linux-musl)
+    sqlite3 (2.9.3-arm64-darwin)
+    sqlite3 (2.9.3-x86_64-darwin)
+    sqlite3 (2.9.3-x86_64-linux-gnu)
+    sqlite3 (2.9.3-x86_64-linux-musl)
    stringio (3.2.0)
    thor (1.5.0)
    tilt (2.7.0)
-    timeout (0.6.0)
+    timeout (0.6.1)
    tsort (0.2.0)
    turbo-rails (2.0.23)
      actionpack (>= 7.1.0)
      railties (>= 7.1.0)
    tzinfo (2.0.6)
      concurrent-ruby (~> 1.0)
+    uri (1.1.1)
    useragent (0.16.11)
    warden (1.2.9)
      rack (>= 2.0.9)
-    web-console (4.2.1)
-      actionview (>= 6.0.0)
-      activemodel (>= 6.0.0)
+    web-console (4.3.0)
+      actionview (>= 8.0.0)
      bindex (>= 0.4.0)
-      railties (>= 6.0.0)
+      railties (>= 8.0.0)
    websocket (1.2.11)
    websocket-driver (0.8.0)
      base64
@@ -315,11 +316,10 @@ DEPENDENCIES
  capybara
  devise
  importmap-rails
-  minitest (< 6)
  mysql2 (~> 0.5)
  pg (~> 1.5)
  puma (~> 6.0)
-  rails (~> 7.2.3)
+  rails (~> 8.1.3)
  sassc-rails
  selenium-webdriver
  sprockets-rails
--- a/README.md
+++ b/README.md
@@ -16,14 +16,10 @@ environment, see the _Contributing_ section below.
 * Server side:
    * Ruby interpreter, depending on the version of Rails used (see _Gemfile_),
        * https://guides.rubyonrails.org/upgrading_ruby_on_rails.html#ruby-versions
-    * database (e.g. MySQL >= 8.0) supporting:
+    * database (e.g. SQLite, MySQL >= 8.0) supporting:
        * recursive Common Table Expressions (CTE) for SELECT/UPDATE/DELETE,
            * MariaDB does not support CTE for UPDATE/DELETE
              (https://jira.mariadb.org/browse/MDEV-18511)
-        * decimal datatype with precision of at least 30,
-            * SQLite3 _flexible typing_ decimal will work, but precision
-              will be limited to 16, making it practical mostly for testing
-              purposes
    * for testing: browser as specified in _Client side_ requirements
 * Client side:
    * browser (e.g. Firefox >= 121) supporting:
@@ -89,14 +85,10 @@ Running

 ### Standalone Rails server + Apache proxy

-Customize Puma config template:
+Copy and customize Puma config template if required:

    cp -a config/puma.rb.dist config/puma.rb

-and specify server IP/port, either with `port` or `bind`, e.g.:
-
-    bind 'tcp://0.0.0.0:3000'
-
 #### (option 1) Start server manually

    bundle exec rails s -e production
@@ -123,9 +115,10 @@ Contributing

 ### Gems

-Apart from database adapter, install development and testing gems:
+Install development and testing gems, including at least MySQL and SQLite
+database adapters:

-    bundle config --local with mysql development test
+    bundle config --local with development test mysql sqlite

 ### Configuration

@@ -138,20 +131,29 @@ assets.

 ### Database

-Grant database user privileges for development and test environments,
-possibly with different Ruby versions:
+Grant database user privileges for development and test environments. Example
+below shows how to grant privileges to all databases which names start with
+`fixinme-` on MySQL:

    > mysql -p
    mysql> create user `fixinme-dev`@localhost identified by '<some password>';
    mysql> grant all privileges on `fixinme-%`.* to `fixinme-dev`@localhost;
    mysql> flush privileges;

+Dumping development data before database reset:
+
+    mysqldump -h <address> -u <user> -p --no-create-info --no-tablespaces --complete-insert <database> > tmp/data.sql
+
 ### Development environment

 Starting application server in development environment:

    bundle exec rails s -e development

+Accessing database console when more than one test db is present:
+
+    bundle exec rails dbconsole -e test --db sqlite3
+
 For running rake tasks, prepend command with environment:

    RAILS_ENV=development bundle exec rails ...
@@ -164,14 +166,22 @@ Tests need to be run from within toplevel application directory:

        bundle exec rails test:system

-* system test(s) with seed/test name specified:
+* system test(s) with seed or test name specified:

-        bundle exec rails test:system --seed 64690 --name test_add_unit
+        bundle exec rails test:system --include test_add_unit --seed 64690

-* all tests from one file, with optional seed:
+* all tests from one file, optionally with seed:

        bundle exec rails test test/system/users_test.rb --seed 1234

+* system tests for selected database configuration (if multiple present):
+
+        bundle exec rails test:system --include /^test_sqlite3_/
+
+* single system test for all database configurations (if multiple present):
+
+        bundle exec rails test:system --include /^test_\\w+_add_unit$/
+
 ### Icons

 Pictogrammers Material Design Icons: https://pictogrammers.com/library/mdi/
--- a/app/assets/images/pictograms/alert-outline.svg
+++ b/app/assets/images/pictograms/alert-outline.svg
@@ -1 +1 @@
-<svg xmlns="http://www.w3.org/2000/svg" id="icon" viewBox="0 0 24 24"><path fill="#ffffff" d="M12,2L1,21H23M12,6L19.53,19H4.47M11,10V14H13V10M11,16V18H13V16" /></svg>
+<svg xmlns="http://www.w3.org/2000/svg" id="icon" viewBox="0 0 24 24"><path d="M12,2L1,21H23M12,6L19.53,19H4.47M11,10V14H13V10M11,16V18H13V16" /></svg>
--- a/app/assets/images/pictograms/check-circle-outline.svg
+++ b/app/assets/images/pictograms/check-circle-outline.svg
@@ -1 +1 @@
-<svg xmlns="http://www.w3.org/2000/svg" id="icon" viewBox="0 0 24 24"><path fill="#ffffff" d="M12 2C6.5 2 2 6.5 2 12S6.5 22 12 22 22 17.5 22 12 17.5 2 12 2M12 20C7.59 20 4 16.41 4 12S7.59 4 12 4 20 7.59 20 12 16.41 20 12 20M16.59 7.58L10 14.17L7.41 11.59L6 13L10 17L18 9L16.59 7.58Z" /></svg>
+<svg xmlns="http://www.w3.org/2000/svg" id="icon" viewBox="0 0 24 24"><path d="M12 2C6.5 2 2 6.5 2 12S6.5 22 12 22 22 17.5 22 12 17.5 2 12 2M12 20C7.59 20 4 16.41 4 12S7.59 4 12 4 20 7.59 20 12 16.41 20 12 20M16.59 7.58L10 14.17L7.41 11.59L6 13L10 17L18 9L16.59 7.58Z" /></svg>
--- a/app/assets/stylesheets/application.css
+++ b/app/assets/stylesheets/application.css
@@ -18,10 +18,12 @@
 /* Strive for simplicity:
 * * style elements/tags only - if possible,
 * * replace element/tag name with class name - if element has to be styled
- * differently depending on context (e.g. form)
+ * differently depending on context (e.g. <form>, <table>, <a> as link/button),
+ * * styles with multiple selectors should have all selectors with same
+ * specificity, to allow proper rule specificity vs order management.
 *
- * NOTE: Style in a modular way, similar to how CSS @scope would be used,
- * to make transition easier once @scope is widely available */
+ * NOTE: style in a modular way, similar to how CSS @scope would be used,
+ * to make transition easier once @scope is widely available. */
 :root {
  --color-focus-gray: #f3f3f3;
  --color-border-gray: #dddddd;
@@ -53,17 +55,36 @@
 :focus-visible {
  outline: none;
 }
+/* NOTE: move to higher priority layer instead of using !important?; add CSS
+ * @layer requirements in README */
+[disabled] {
+  border-color: var(--color-border-gray) !important;
+  color: var(--color-border-gray) !important;
+  /* NOTE: cannot set cursor when `pointer-events: none`; can be fixed by setting
+   * `cursor` on wrapping element.
+  cursor: not-allowed; */
+  fill: var(--color-border-gray) !important;
+  pointer-events: none !important;
+}
+/* Styles set `display` without distinguishing between [hidden] elements, making
+ * them visible. */
+[hidden] {
+  display: none !important;
+}


 /* Color coding of input controls' background:
- *  blue - target for interaction with pointer
- *  gray - target for interaction with keyboard
- *  red - destructive, non-undoable action
+ *  blue - target for interaction with pointer,
+ *  gray - target for interaction with keyboard,
+ *  red - destructive, non-undoable action.
 */
+/* TODO: merge selectors using :is() */
+a,
 button,
 details,
 input,
 select,
+summary,
 textarea {
  background-color: inherit;
  font: inherit;
@@ -73,56 +94,24 @@ input,
 select {
  text-align: inherit;
 }
-a,
-button,
-input[type=submit] {
-  cursor: pointer;
-  text-decoration: none;
-  white-space: nowrap;
-}
-/* [hidden] submit controls cannot have `display` set as it makes them visible */
-.button,
-button:not([hidden]),
-input[type=submit]:not([hidden]),
-.tab {
-  align-items: center;
-  color: var(--color-gray);
-  display: flex;
-  fill: var(--color-gray);
-  font-weight: bold;
-}
-.button,
-button,
-input[type=submit] {
-  font-size: 0.8rem;
-  padding: 0.6em 0.5em;
-  width: fit-content;
-}
-input:not([type=submit]):not([type=checkbox]),
-select,
-summary,
-textarea {
-  padding: 0.2em 0.4em;
-}
-.button,
-button,
 input,
 select,
 summary,
 textarea {
-  border: solid 1px var(--color-gray);
+  border: 1px solid var(--color-gray);
  border-radius: 0.25em;
+  padding: 0.2em 0.4em;
 }
-[name=cancel],
-.auxiliary {
-  border-color: var(--color-border-gray);
-  color: var(--color-nav-gray);
-  fill: var(--color-nav-gray);
+svg {
+  height: 1.4em;
+  margin: 0 0.2em 0 0;
+  width: 1.4em;
+}
+svg:last-child {
+  margin-right: 0;
 }
-input[type=checkbox],
-svg,
 textarea {
-  margin: 0
+  margin: 0;
 }
 input[type=checkbox] {
  accent-color: var(--color-blue);
@@ -130,17 +119,20 @@ input[type=checkbox] {
  -webkit-appearance: none;
  display: flex;
  height: 1.1em;
+  margin: 0;
+  padding: 0;
  width: 1.1em;
 }
 input[type=checkbox]:checked {
  appearance: checkbox;
  -webkit-appearance: checkbox;
 }
-/* Hide spin buttons in input number fields */
-/* TODO: add spin buttons inside input[number]: before (-) and after (+) input */
+/* Hide spin buttons of <input type=number>. */
+/* TODO: add spin buttons inside <input type=number>: before (-) and after (+) input. */
 input[type=number] {
  appearance: textfield;
  -moz-appearance: textfield;
+  text-align: end;
 }
 input::-webkit-inner-spin-button {
  -webkit-appearance: none;
@@ -149,37 +141,113 @@ input::-webkit-outer-spin-button {
  -webkit-appearance: none;
  margin: 0;
 }
-.button > svg,
-.tab > svg,
-button > svg {
-  height: 1.4em;
-  width: 1.4em;
+/* Text color of table form controls:
+ *  - black for row/table forms,
+ *  - inherited for internal (column specific) buttons/forms. */
+table input,
+table select,
+table summary,
+table textarea {
+  border-color: var(--color-border-gray);
 }
-.button > svg:not(:last-child),
-.tab > svg:not(:last-child),
-button > svg:not(:last-child) {
-  margin-right: 0.2em;
+table input,
+table select,
+table textarea {
+  padding-block: 0.375em;
 }
-/* TODO: move normal non-button links (<a>:hover/:focus) styling here (i.e.
- * page-wide, top-level) and remove from table.items - as the style should be
- * same everywhere */
-.button:focus-visible,
-button:focus-visible,
-input[type=submit]:focus-visible {
-  background-color: var(--color-focus-gray);
+table form input,
+table form select,
+table form summary,
+table form textarea {
+  color: inherit;
+}
+table svg:not(:only-child) {
+  height: 1.25em;
+  width: 1.25em;
 }
 input:focus-visible,
 select:focus-visible,
 select:focus-within,
-/* TODO: how to achieve summary:focus-within for ::details-content? */
+/* TODO: how to achieve `summary:focus-within` for `::details-content`? */
 summary:focus-visible,
 textarea:focus-visible {
  accent-color: var(--color-dark-blue);
  background-color: var(--color-focus-gray);
+  color: black;
 }
-.button:hover,
-button:hover,
-input[type=submit]:hover {
+input:hover,
+select:hover,
+summary:hover,
+textarea:hover {
+  border-color: var(--color-blue);
+  outline: 1px solid var(--color-blue);
+}
+select:hover,
+summary:hover {
+  color: black;
+  cursor: pointer;
+}
+/* TODO: style <details>/<summary> focus to match <select> as much as possible.
+summary:focus-visible::before,
+summary:hover::before {
+  background-color: black;
+}
+ */
+input:invalid,
+select:invalid,
+textarea:invalid {
+  border-color: var(--color-red);
+  outline-color: var(--color-red);
+}
+
+/* `.button`: button-styled <a>, <button>, <input type=submit>.
+ * `.link`: any other <a>.
+ * `.tab`: tab-styled <a>.
+ */
+.button,
+.link,
+.tab {
+  cursor: pointer;
+  text-decoration: none;
+  white-space: nowrap;
+}
+.button,
+.tab {
+  align-items: center;
+  color: var(--color-gray);
+  display: flex;
+  fill: var(--color-gray);
+  font-weight: bold;
+}
+.button {
+  border: 1px solid var(--color-gray);
+  border-radius: 0.25em;
+  font-size: 0.8rem;
+  padding: 0.6em 0.5em;
+  width: fit-content;
+}
+.link {
+  color: inherit;
+  text-decoration: underline 1px var(--color-border-gray);
+  text-underline-offset: 0.25em;
+}
+.auxiliary {
+  border-color: var(--color-nav-gray);
+  color: var(--color-nav-gray);
+  fill: var(--color-nav-gray);
+}
+table .button {
+  border-color: var(--color-border-gray);
+  font-weight: normal;
+  height: 100%;
+  padding: 0.4em;
+}
+.button:focus-visible,
+.tab:focus-visible,
+.tab:hover {
+  background-color: var(--color-focus-gray);
+}
+.button:hover {
  background-color: var(--color-blue);
  border-color: var(--color-blue);
  color: white;
@@ -189,32 +257,17 @@ input[type=submit]:hover {
  background-color: var(--color-red);
  border-color: var(--color-red);
 }
-input:hover,
-select:hover,
-summary:hover,
-textarea:hover {
-  border-color: var(--color-blue);
-  outline: solid 1px var(--color-blue);
+.link:focus-visible {
+  text-decoration-color: var(--color-gray);
 }
-select:hover,
-summary:hover {
-  cursor: pointer;
-}
-input:invalid,
-select:invalid,
-textarea:invalid {
-  border-color: var(--color-red);
-  outline: solid 1px var(--color-red);
-}
-input[type=text]:read-only,
-textarea:read-only {
-  border: none;
-  padding-inline: 0;
+.link:hover {
+  color: var(--color-blue);
+  text-decoration-color: var(--color-blue);
 }


-/* NOTE: collapse gaps around empty rows (`topside`) once possible
- * with grid-collapse property and remove alternative grid-template
+/* NOTE: collapse gaps around empty rows (`topside`) once possible with
+ * `grid-collapse` property and remove alternative `grid-template-areas`.
 * https://github.com/w3c/csswg-drafts/issues/5813 */
 body {
  display: grid;
@@ -222,16 +275,16 @@ body {
  grid-template-areas:
    "header    header  header"
    "nav       nav     nav"
-    "leftside  topside rightside"
    "leftside  main    rightside";
  grid-template-columns: 1fr minmax(max-content, 2fr) 1fr;
  font-family: system-ui;
  margin: 0.4em;
 }
-body:not(:has(.topside-area)) {
+body:has(> .topside-area) {
  grid-template-areas:
    "header    header  header"
    "nav       nav     nav"
+    "leftside  topside rightside"
    "leftside  main    rightside";
 }

@@ -247,18 +300,14 @@ header {
  margin-inline-start: 4%;
 }
 .navigation > .tab {
-  border-bottom: solid 2px var(--color-nav-gray);
+  border-bottom: 2px solid var(--color-nav-gray);
  flex: 1;
  font-size: 1rem;
  justify-content: center;
  padding-block: 0.4em;
 }
-.navigation > .tab:hover,
-.navigation > .tab:focus-visible {
-  background-color: var(--color-focus-gray);
-}
 .navigation > .tab.active {
-  border-bottom: solid 4px var(--color-blue);
+  border-bottom: 4px solid var(--color-blue);
  color: var(--color-blue);
  fill: var(--color-blue);
 }
@@ -290,7 +339,7 @@ header {

 #flashes {
  display: grid;
-  gap: 0.2em;
+  row-gap: 0.4em;
  grid-template-columns: 1fr auto auto auto 1fr;
  left: 0;
  pointer-events: none;
@@ -306,49 +355,42 @@ header {
  display: grid;
  grid-column: 2/5;
  grid-template-columns: subgrid;
+  line-height: 2.2em;
  pointer-events: auto;
 }
-.flash.alert:before {
-  content: url('pictograms/alert-outline.svg');
+.flash::before {
+  filter: invert(1);
  height: 1.4em;
  margin: 0 0.5em;
  width: 1.4em;
 }
+.flash.alert::before {
+  content: url('pictograms/alert-outline.svg');
+}
 .flash.alert {
  border-color: var(--color-red);
  background-color: var(--color-red);
 }
-.flash.notice:before {
+.flash.notice::before {
  content: url('pictograms/check-circle-outline.svg');
-  height: 1.4em;
-  margin: 0 0.5em;
-  width: 1.4em;
 }
 .flash.notice {
  border-color: var(--color-blue);
  background-color: var(--color-blue);
 }
-.flash > div {
-  grid-column: 2;
-}
-/* NOTE: currently flash button inherits some unnecessary styles from generic
- * button. */
-.flash > button {
-  border: none;
-  color: inherit;
+.flash svg {
  cursor: pointer;
-  font-size: 1.4em;
-  font-weight: bold;
-  grid-column: 3;
+  fill: white;
+  height: 2.2em;
  opacity: 0.6;
-  padding: 0.2em 0.4em;
+  padding: 0.4em 0.5em;
+  width: 2.4em;
 }
-.flash > button:hover {
+.flash svg:hover {
  opacity: 1;
 }


-/* TODO: Hover over invalid should work like in measurements (thin vs thick border) */
 .labeled-form {
  align-items: center;
  display: grid;
@@ -365,7 +407,7 @@ header {
 .labeled-form label.required {
  font-weight: bold;
 }
-/* Don't style `label.error + input` if case already covered by input:invalid */
+/* Don't style `label.error + input` if case already covered by `input:invalid`. */
 .labeled-form label.error {
  color: var(--color-red);
 }
@@ -385,200 +427,120 @@ header {
 .labeled-form .auxiliary {
  grid-column: 3;
  /* If more buttons are needed, `grid-row` can be replaced with
-   * `reading-flow: grid-columns` to ensure proper tabindex order */
+   * `reading-flow: grid-columns` to ensure proper [tabindex] order. */
  grid-row: 1;
  height: 100%;
  padding-block: 0;
 }

-
-/* TODO: remove .items class (?) and make 'form table' work properly */
-table.items {
+.tabular-form table {
+  border: none;
  border-spacing: 0;
-  border: solid 1px var(--color-border-gray);
+}
+.tabular-form table td {
+  border: none;
+  padding-inline-start: 0.4em;
+  vertical-align: middle;
+}
+.tabular-form table td:first-child {
+  padding-inline-start: 0;
+}
+.tabular-form table td:last-child {
+  padding-inline-end: 0;
+}
+.tabular-form table :is(form, input, select, textarea):only-child {
+  margin-inline-start: 0;
+}
+
+
+.items-table {
+  border-spacing: 0;
+  border: 1px solid var(--color-border-gray);
  border-radius: 0.25em;
  font-size: 0.85rem;
  text-align: left;
 }
-table:not(:has(tr)) {
-  display: none;
-}
-table.items thead {
+.items-table thead {
  font-size: 0.8rem;
 }
-table.items thead,
-table.items tbody tr:hover {
+.items-table thead,
+.items-table tbody tr:hover {
  background-color: var(--color-focus-gray);
 }
-table.items th {
-  padding-block: 0.75em;
+.items-table th {
+  padding: 0.75em 0 0.75em 1em;
  text-align: center;
 }
-table.items th,
-table.items td {
-  padding-inline: 1em 0;
-}
-/* For <a> to fill <td> completely, we use an ::after pseudoelement. */
-table.items td.link {
-  padding: 0;
-  position: relative;
-}
-table.items td.link a {
-  color: inherit;
-  font: inherit;
-}
-table.items td.link a::after {
-  content: '';
-  inset: 0;
-  position: absolute;
-}
-table.items td:first-child {
-  padding-inline-start: calc(1em + var(--depth) * 0.8em);
-}
-table.items td:has(input, select, textarea) {
-  padding-inline-start: calc(0.6em - 0.9px);
-}
-table.items td:first-child:has(input, select, textarea) {
-  padding-inline-start: calc(0.6em + var(--depth) * 0.8em - 0.9px);
-}
-table.items th:last-child {
+.items-table th:last-child {
  padding-inline-end: 0.4em;
 }
-table.items td:last-child {
+.items-table td {
+  border-top: 1px solid var(--color-border-gray);
+  height: 2.4em;
+  padding: 0.1em 0 0.1em calc(1em + var(--depth) * 0.8em);
+}
+.items-table td:last-child {
  padding-inline-end: 0.1em;
 }
-table.items td {
-  border-top: solid 1px var(--color-border-gray);
-  height: 2.4em;
-  padding-block: 0.1em;
+.items-table :is(form, input, select, textarea):only-child {
+  margin-inline-start: calc(-0.4em - 0.9px);
 }
-table.items .actions {
-  display: flex;
+/* For <a> to fill table cell completely, we use an `::after` pseudoelement. */
+/* TODO: expand to whole row? will require adjusting z-index on inputs/buttons */
+.items-table td:has(> .link) {
+  position: relative;
+}
+.items-table .link::after {
+  content: '';
+  inset: -1px 0 0 0;
+  position: absolute;
+}
+.items-table .flex {
  gap: 0.4em;
  justify-content: end;
 }
-table.items .actions.centered {
-  justify-content: center;
-}
-table.items tr.dropzone {
+.items-table .dropzone {
  position: relative;
 }
-table.items tr.dropzone::after {
+.items-table .dropzone::after {
  content: '';
  inset: 1px 0 0 0;
  position: absolute;
-  outline: dashed 2px var(--color-blue);
+  outline: 2px dashed var(--color-blue);
  outline-offset: -1px;
  z-index: var(--z-index-table-row-outline);
 }
-table.items td.handle {
-  cursor: move;
+.items-table .handle {
+  cursor: grab;
 }
-table.items tr.form td {
+.items-table .form td {
  vertical-align: top;
 }
-
-/* TODO: replace :hover:focus-visible combos with proper LOVE stye order */
-/* TODO: Update table styling: simplify selectors, deduplicate, remove non-font rem. */
-table.items td.link a:hover,
-table.items td.link a:focus-visible,
-table.items td.link a:hover:focus-visible {
-  text-decoration: underline;
-  text-decoration-thickness: 0.05rem;
-  text-underline-offset: 0.2rem;
-}
-table.items td.link a:hover {
-  color: var(--color-blue);
-}
-table.items td.link a:focus-visible {
-  text-decoration-color: var(--color-gray);
-}
-table.items td.link a:hover:focus-visible {
-  color: var(--color-dark-blue);
-}
-
-table.items td:not(:first-child),
+.items-table td:not(:first-child),
 .grayed {
  color: var(--color-table-gray);
-  fill: var(--color-table-gray);
+  fill: var(--color-gray);
 }
-table.items svg {
-  height: 1rem;
-  vertical-align: middle;
-  width: 1rem;
-}
-table.items svg:last-child {
-  height: 1.2rem;
-  width: 1.2rem;
-}
-table.items td.svg {
+.items-table td:has(> svg:only-child) {
  text-align: center;
 }
-table.items td.number {
-  text-align: right;
-}
-table.items .button,
-table.items button,
-table.items input[type=submit] {
-  font-weight: normal;
-  height: 100%;
-  padding: 0.4em;
-}
-table.items input:not([type=submit]):not([type=checkbox]),
-table.items select,
-table.items textarea {
-  padding-block: 0.375em;
-}
-/* TODO: find a way (layers?) to style inputs differently while making sure
- * hover works properly without using :not(:hover) selectors here. */
-table.items .button:not(:hover),
-table.items button:not(:hover),
-table.items input:not(:hover),
-table.items select:not(:hover),
-table.items textarea:not(:hover) {
-  border-color: var(--color-border-gray);
-}
-table.items .button:not(:hover),
-table.items button:not(:hover),
-table.items input[type=submit]:not(:hover),
-table.items select:not(:hover) {
-  color: var(--color-table-gray);
-}
-table.items select:focus-within,
-table.items select:focus-visible {
-  color: black;
-}
-form table.items {
-  border: none;
-}
-form table.items td {
-  border: none;
-  text-align: left;
-  vertical-align: middle;
-}
-form table.items td:first-child {
-  color: inherit;
-}


-.centered {
+.center {
  margin: 0 auto;
 }
-.extendedright {
-  margin-right: auto;
-}
 .hexpand {
  width: 100%;
 }
-.hflex {
+.flex {
  display: flex;
  gap: 0.8em;
 }
-.hflex.reverse {
+.flex.reverse {
  flex-direction: row-reverse;
 }
-.hflex.centered {
-  justify-content: center;
+.flex.vertical {
+  flex-direction: column;
 }
 .hint {
  color: var(--color-table-gray);
@@ -586,21 +548,18 @@ form table.items td:first-child {
  font-size: 0.9rem;
  text-align: center;
 }
-.vflex {
-  display: flex;
-  gap: 0.8em;
-  flex-direction: column;
+.hmin50 {
+  min-width: 50%;
 }
-[disabled] {
-/* label:has(input[disabled]) {
- * TODO: disabled checkbox blue square focus removal; disabled label styling;
- * focused label styling (currently only checkbox has focus)
- * */
-  border-color: var(--color-border-gray) !important;
-  color: var(--color-border-gray) !important;
-  cursor: not-allowed;
-  fill: var(--color-border-gray) !important;
-  pointer-events: none;
+.italic {
+  color: var(--color-gray);
+  font-style: italic;
+}
+.ralign {
+  text-align: right;
+}
+.rextend {
+  margin-right: auto;
 }


@@ -612,12 +571,12 @@ summary {
  align-items: center;
  color: var(--color-gray);
  display: flex;
-  gap: 0.2em;
+  gap: 0.4em;
  height: 100%;
  white-space: nowrap;
 }
 summary::before {
-  background-color: #000;
+  background-color: currentColor;
  content: "";
  height: 1em;
  mask-image: url('pictograms/chevron-down.svg');
@@ -629,7 +588,7 @@ summary:has(.button) {
  padding-inline-end: 0;
 }
 summary .button {
-  border: solid 1px var(--color-border-gray);
+  border: 1px solid var(--color-border-gray);
  border-radius: inherit;
  border-top-left-radius: 0;
  border-bottom-left-radius: 0;
@@ -640,15 +599,15 @@ summary span {
  width: 100%;
 }
 details[open] summary::before {
-  transform: rotate(180deg);
+  transform: scaleY(-1);
 }
 summary::marker {
  padding-left: 0.25em;
 }
-/* NOTE: use details[open]::details-content once widely available */
+/* NOTE: use `details[open]::details-content` once widely available. */
 details[open] ul {
-  background: white;
-  border: solid 1px var(--color-border-gray);
+  background-color: white;
+  border: 1px solid var(--color-border-gray);
  border-radius: 0.25em;
  box-shadow: 1px 1px 3px var(--color-border-gray);
  margin: -1px 0 0 0;
@@ -670,3 +629,15 @@ li input[type=checkbox] {
 li::marker {
  content: '';
 }
+/*
+ * TODO:
+ * * disable <label> containing disabled checkbox: `label:has(input[disabled])`,
+ * * disabled label styling,
+ * * focused label styling (currently only checkbox has focus),
+ * * disabled checkbox blue square focus removal.
+ * */
+
+#measurement_form {
+  min-width: 66%;
+  width: max-content;
+}
--- a/app/controllers/readouts_controller.rb
+++ b/app/controllers/readouts_controller.rb
@@ -6,7 +6,7 @@ class ReadoutsController < ApplicationController
  def new
    @quantities -= @prev_quantities
    # TODO: raise ParameterInvalid if new_quantities.empty?
-    @readouts = current_user.readouts.build(@quantities.map { |q| {quantity: q} })
+    @readouts = @quantities.map { |q| q.readouts.build }

    @user_units = current_user.units.ordered

--- a/app/controllers/units_controller.rb
+++ b/app/controllers/units_controller.rb
@@ -17,7 +17,7 @@ class UnitsController < ApplicationController
  end

  def create
-    @unit = current_user.units.new(unit_params)
+    @unit = current_user.units.new(params.expect(Unit::ATTRIBUTES))
    if @unit.save
      @before = @unit.successive
      flash.now[:notice] = t('.success', unit: @unit)
@@ -30,7 +30,7 @@ class UnitsController < ApplicationController
  end

  def update
-    if @unit.update(unit_params.except(:base_id))
+    if @unit.update(params.except(:base_id).expect(Unit::ATTRIBUTES))
      flash.now[:notice] = t('.success', unit: @unit)
    else
      render :edit
@@ -40,11 +40,11 @@ class UnitsController < ApplicationController
  # TODO: Avoid double table width change by first un-hiding table header,
  # then displaying index, e.g. by re-displaying header in index
  def rebase
-    permitted = params.require(:unit).permit(:base_id)
-    permitted.merge!(multiplier: 1) if permitted[:base_id].blank? && @unit.multiplier != 1
+    unit_params = params.expect(unit: :base_id)
+    unit_params.merge!(multiplier: 1.0) if unit_params[:base_id].blank?

    @previous_base = @unit.base
-    @unit.update!(permitted)
+    @unit.update!(unit_params)

    @before = @unit.successive
    if @unit.multiplier_previously_changed?
@@ -59,10 +59,6 @@ class UnitsController < ApplicationController

  private

-  def unit_params
-    params.require(:unit).permit(Unit::ATTRIBUTES)
-  end
-
  def find_unit
    @unit = current_user.units.find_by!(id: params[:id])
  end
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -12,6 +12,12 @@ module ApplicationHelper
      labeled_field_for(method, options) { super }
    end

+    def submit(value = nil, options = {})
+      value, options = nil, value if value.is_a?(Hash)
+      options[:class] = @template.class_names('button', options[:class])
+      super
+    end
+
    private

    def labeled_field_for(method, options)
@@ -96,20 +102,32 @@ module ApplicationHelper

    def number_field(method, options = {})
      attr_type = object.type_for_attribute(method)
-      if attr_type.type == :decimal
+      case attr_type.type
+      when :float, :double
        options[:value] = object.public_send(method)&.to_scientific
-        options[:step] ||= BigDecimal(10).power(-attr_type.scale)
-        options[:max] ||= BigDecimal(10).power(attr_type.precision - attr_type.scale) -
-          options[:step]
-        options[:min] = options[:min] == :step ? options[:step] : options[:min]
-        options[:min] ||= -options[:max]
+        options[:step] ||= :any
+        options[:min] ||= Float::MIN_15
+        options[:max] ||= Float::MAX_15
+        # Longest possible number (written not using exponent):
+        #   sign (1), leading 0 (1), dot (1), exponent 0s (307), digits (15).
+        # This is only upper bound, which cannot guarantee the number won't fall
+        # out of range.
+        # TODO: add `[pattern]` to limit precision and (possibly) replace `[maxlength]`?
+        # NOTE: `[pattern]` is unavailable on `input[type=number]` and `[min]/[max]` is
+        # unavailable on `input[type=text]`.
+        options[:maxlength] ||= 3 + Float::MIN_10_EXP + Float::DIG
+        options[:size] ||= 6
      end
      super
    end

    def button(value = nil, options = {}, &block)
-      # button does not use #objectify_options
-      options.merge!(@options.slice(:form))
+      # #button does not use #objectify_options/@default_options
+      value, options = nil, value if value.is_a?(Hash)
+      options = options.merge(
+        @default_options.slice(:form),
+        class: @template.class_names('button', options[:class])
+      )
      super
    end

@@ -138,12 +156,14 @@ module ApplicationHelper
  end

  def tabular_form_with(**options, &block)
-    extra_options = {builder: TabularFormBuilder, html: {autocomplete: 'off'}}
+    extra_options = {builder: TabularFormBuilder, class: 'tabular-form',
+                     html: {autocomplete: 'off'}}
    form_with(**merge_attributes(options, extra_options), &block)
  end

  def svg_tag(source, label = nil, options = {})
-    svg_tag = tag.svg(options) do
+    label, options = nil, label if label.is_a? Hash
+    svg_tag = tag.svg(**options) do
      tag.use(href: "#{image_path(source + ".svg")}#icon")
    end
    label.blank? ? svg_tag : svg_tag + tag.span(label)
@@ -192,9 +212,7 @@ module ApplicationHelper

  def image_link_to_unless_current(name, image = nil, options = nil, html_options = {})
    name, html_options = link_or_button_options(:link, name, image, html_options)
-    # NOTE: Starting from Rails 8.1.0, below condition can be replaced with:
-    #   current_page?(options, method: [:get, :post])
-    if request.path == url_for(options)
+    if current_page?(options, method: [:get, :post])
      html_options = html_options.deep_merge DISABLED_ATTRIBUTES
    end
    link_to name, options, html_options
@@ -212,9 +230,8 @@ module ApplicationHelper
      # Conversion of flash to Array only required because of Devise
      Array(messages).map do |message|
        tag.div class: "flash #{entry}" do
-          # TODO: change button text to svg to make it aligned vertically
-          tag.div(sanitize(message)) + tag.button(sanitize("&times;"), tabindex: -1,
-                                                  onclick: "this.parentElement.remove();")
+          tag.span(sanitize(message)) +
+            svg_tag('pictograms/close-outline', {onclick: "this.parentElement.remove()"})
        end
      end
    end.join.html_safe
--- a/app/helpers/quantities_helper.rb
+++ b/app/helpers/quantities_helper.rb
@@ -1,9 +1,9 @@
 module QuantitiesHelper
-  def quantities_check_boxes
+  def quantities_check_boxes(quantities)
    # Closing <details> on focusout event depends on relatedTarget for internal
    # actions being non-null. To ensure this, all top-layer elements of
    # ::details-content must accept focus, e.g. <label> needs tabindex="-1" */
-    collection_check_boxes(nil, :quantity, @quantities, :id, :to_s_with_depth,
+    collection_check_boxes(nil, :quantity, quantities, :id, :to_s_with_depth,
                           include_hidden: false) do |b|
      content_tag :li, b.label(tabindex: -1) { b.check_box + b.text }
    end
--- a/app/models/note.rb
+++ b/app/models/note.rb
@@ -0,0 +1,3 @@
+class Note < ApplicationRecord
+  ATTRIBUTES = [:text]
+end
--- a/app/models/quantity.rb
+++ b/app/models/quantity.rb
@@ -6,6 +6,7 @@ class Quantity < ApplicationRecord
  belongs_to :parent, optional: true, class_name: "Quantity"
  has_many :subquantities, ->{ order(:name) }, class_name: "Quantity",
    inverse_of: :parent, dependent: :restrict_with_error
+  has_many :readouts, dependent: :restrict_with_error

  validate if: ->{ parent.present? } do
    errors.add(:parent, :user_mismatch) unless user_id == parent.user_id
--- a/app/models/readout.rb
+++ b/app/models/readout.rb
@@ -4,4 +4,6 @@ class Readout < ApplicationRecord
  belongs_to :user
  belongs_to :quantity
  belongs_to :unit
+
+  # TODO: validate quantity.user_id == unit.user_id != NULL
 end
--- a/app/models/unit.rb
+++ b/app/models/unit.rb
@@ -1,5 +1,5 @@
 class Unit < ApplicationRecord
-  ATTRIBUTES = [:symbol, :description, :multiplier, :base_id]
+  ATTRIBUTES = {unit: [:symbol, :description, :multiplier, :base_id]}

  belongs_to :user, optional: true
  belongs_to :base, optional: true, class_name: "Unit"
@@ -14,8 +14,8 @@ class Unit < ApplicationRecord
  validates :symbol, presence: true, uniqueness: {scope: :user_id},
    length: {maximum: type_for_attribute(:symbol).limit}
  validates :description, length: {maximum: type_for_attribute(:description).limit}
-  validates :multiplier, numericality: {equal_to: 1}, unless: :base
-  validates :multiplier, numericality: {greater_than: 0, precision: true, scale: true}, if: :base
+  validates :multiplier, numericality: {equal_to: 1.0}, unless: :base
+  validates :multiplier, numericality: {greater_than: 0.0}, if: :base

  scope :defaults, ->{ where(user: nil) }
  scope :defaults_diff, ->{
@@ -26,8 +26,10 @@ class Unit < ApplicationRecord
    other_bases_units = arel_table.alias('other_bases_units')
    sub_units = arel_table.alias('sub_units')

+    # TODO: move inner 'with' CTE to outer 'with recursive' - it can have multiple
+    # CTEs, even non recursive ones.
    Unit.with_recursive(actionable_units: [
-      self.or(Unit.defaults).left_joins(:base)
+      Unit.with(units: self.or(Unit.defaults)).left_joins(:base)
        .where.not(
          # Exclude Units that are/have default counterpart
          Arel::SelectManager.new.project(1).from(other_units)
@@ -63,14 +65,8 @@ class Unit < ApplicationRecord
        ),
      # Fill base Units to display proper hierarchy. Duplicates will be removed
      # by final group() - can't be deduplicated with UNION due to 'portable' field.
-      # Use ActiveRecord::Relation (not a raw SelectManager) so the SQLite Arel
-      # visitor does not wrap it in parentheses inside the UNION ALL CTE body.
-      Unit.joins(
-        arel_table.create_join(
-          actionable_units,
-          arel_table.create_on(actionable_units[:base_id].eq(arel_table[:id]))
-        )
-      ).select(arel_table[Arel.star], Arel::Nodes.build_quoted(nil).as('portable'))
+      arel_table.join(actionable_units).on(actionable_units[:base_id].eq(arel_table[:id]))
+        .project(arel_table[Arel.star], Arel::Nodes.build_quoted(nil).as('portable'))
    ]).select(units: [:base_id, :symbol])
      .select(
        units[:id].minimum.as('id'), # can be ANY_VALUE()
@@ -78,19 +74,17 @@ class Unit < ApplicationRecord
        Arel::Nodes.build_quoted(1).as('multiplier'), # disregard multiplier when sorting
        units[:portable].minimum.as('portable')
      )
-      .from(units).group(units[:base_id], units[:symbol])
+      .from(units).group(:base_id, :symbol)
  }
  scope :ordered, ->{
-    left_outer_joins(:base).order(ordering)
+    left_outer_joins(:base).order([
+      arel_table.coalesce(Arel::Table.new(:bases_units)[:symbol], arel_table[:symbol]),
+      arel_table[:base_id].not_eq(nil),
+      arel_table[:multiplier],
+      arel_table[:symbol]
+    ])
  }

-  def self.ordering
-    [arel_table.coalesce(Arel::Table.new(:bases_units)[:symbol], arel_table[:symbol]),
-     arel_table[:base_id].not_eq(nil),
-     arel_table[:multiplier],
-     arel_table[:symbol]]
-  end
-
  before_destroy do
    # TODO: disallow destruction if any object depends on this unit
    nil
@@ -108,21 +102,21 @@ class Unit < ApplicationRecord
    user_id.nil?
  end

-  # Should only by invoked on Units returned from #defaults_diff which are #portable
+  # Should only by invoked on Units returned from #defaults_diff which are #portable.
  def port!(recipient)
    recipient_base = base && Unit.find_by!(symbol: base.symbol, user: recipient)
-    params = slice(ATTRIBUTES - [:symbol, :base_id])
+    params = slice(ATTRIBUTES[:unit] - [:symbol, :base_id])
    Unit.find_or_initialize_by(user: recipient, symbol: symbol)
      .update!(base: recipient_base, **params)
  end

  def successive
    units = Unit.arel_table
-    lead = Arel::Nodes::NamedFunction.new('LAG', [units[:id]])
-    window = Arel::Nodes::Window.new.order(*Unit.ordering)
-    lag_id = lead.over(window).as('lag_id')
-    Unit.with(
-      units: user.units.left_outer_joins(:base).select(units[Arel.star], lag_id)
-    ).where(units[:lag_id].eq(id)).first
+    Unit.with(units_with_lag: user.units.left_outer_joins(:base).select(
+      units[Arel.star],
+      Arel::Nodes::NamedFunction.new('LAG', [units[:id]])
+        .over(Arel::Nodes::Window.new.order(Unit.ordered.order_values)).as('lag_id')
+    )).from(Arel::Table.new(:units_with_lag).as(:units))
+      .where(units[:lag_id].eq(id)).take
  end
 end
--- a/app/views/default/units/_unit.html.erb
+++ b/app/views/default/units/_unit.html.erb
@@ -5,7 +5,7 @@
  </td>

  <% if current_user.at_least(:active) %>
-    <td class="actions">
+    <td class="flex">
      <% unless unit.portable.nil? %>
        <% if unit.default? %>
          <%= image_button_to_if unit.portable?, t('.import'), 'download-outline',
--- a/app/views/default/units/index.html.erb
+++ b/app/views/default/units/index.html.erb
@@ -8,7 +8,7 @@
    class: 'tools-area' %>
 </div>

-<table class="main-area items">
+<table class="main-area items-table">
  <thead>
    <tr>
      <th><%= Unit.human_attribute_name(:symbol) %></th>
--- a/app/views/layouts/application.html.erb
+++ b/app/views/layouts/application.html.erb
@@ -23,10 +23,10 @@
  </head>

  <body>
-    <header class="hflex">
+    <header class="flex">
      <%= image_link_to t(".source_code"), "code-braces", source_code_url %>
      <%= image_link_to t(".issue_tracker"), "bug-outline", issue_tracker_url,
-            class: "extendedright" %>
+        class: "rextend" %>
      <% if user_signed_in? %>
        <%= image_link_to_unless_current(current_user, "account-wrench-outline",
          edit_user_registration_path) %>
--- a/app/views/measurements/_form.html.erb
+++ b/app/views/measurements/_form.html.erb
@@ -1,30 +1,39 @@
 <%= tabular_form_with model: Measurement.new, id: :measurement_form,
-  class: 'topside-area vflex', html: {onkeydown: 'formProcessKey(event)'} do |form| %>
-  <table class="items centered">
-    <tbody id="readouts"></tbody>
+  class: 'topside-area flex vertical center',
+  html: {onkeydown: 'formProcessKey(event)'} do |form| %>
+
+  <table class="items-table center">
+    <tbody id="readouts">
+      <%= tabular_fields_for @measurement do |form| %>
+        <tr class="italic">
+          <td class="hexpand hmin50"><%= t '.taken_at_html' %></td>
+          <td colspan="3" class="ralign">
+            <%= form.datetime_field :taken_at, required: true %>
+          </td>
+        </tr>
+      <% end %>
+    </tbody>
  </table>

-  <div class="hflex">
-    <%# TODO: right-click selection %>
-    <details id="quantity_select" class="hexpand" open
-             onkeydown="detailsProcessKey(event)">
-      <summary autofocus>
-        <!-- TODO: Set content with CSS when span empty to avoid duplication -->
-        <span data-prompt="<%= t('.select_quantity') %>">
-          <%= t('.select_quantity') %>
-        </span>
-        <%= image_button_tag t(:apply), "update", name: nil, disabled: true,
-          formaction: new_readout_path, formmethod: :get, formnovalidate: true,
-          data: {turbo_stream: true} %>
-      </summary>
-      <ul><%= quantities_check_boxes %></ul>
-    </details>
-    <%= form.button id: :create_measurement_button, disabled: true -%>
-  </div>
+  <%# TODO: right-click selection; unnecessary with hierarchical tags? %>
+  <details id="quantity_select" class="center hexpand" open
+           onkeydown="detailsProcessKey(event)">
+    <summary autofocus>
+      <!-- TODO: Set content with CSS when span empty to avoid duplication -->
+      <span data-prompt="<%= t('.select_quantity') %>">
+        <%= t('.select_quantity') %>
+      </span>
+      <%= image_button_tag t(:apply), "update", name: nil, disabled: true,
+        formaction: new_readout_path, formmethod: :get, formnovalidate: true,
+        data: {turbo_stream: true} %>
+    </summary>
+    <ul><%= quantities_check_boxes(@quantities) %></ul>
+  </details>

-  <div class="hflex reverse">
+  <div class="flex reverse">
+    <%= form.button id: :create_measurement_button, disabled: true -%>
    <%= image_link_to t(:cancel), "close-outline", measurements_path, name: :cancel,
-      class: 'dangerous', onclick: render_turbo_stream('form_close') %>
+      class: 'auxiliary dangerous', onclick: render_turbo_stream('form_close') %>
  </div>
 <% end %>

--- a/app/views/quantities/_form.html.erb
+++ b/app/views/quantities/_form.html.erb
@@ -9,7 +9,7 @@
      <%= form.text_area :description, cols: 30, rows: 1, escape: false %>
    </td>

-    <td class="actions">
+    <td class="flex">
      <%= form.button %>
      <%= image_link_to t(:cancel), "close-outline", quantities_path, class: 'dangerous',
        name: :cancel, onclick: render_turbo_stream('form_close', {row: row}) %>
--- a/app/views/quantities/_quantity.html.erb
+++ b/app/views/quantities/_quantity.html.erb
@@ -5,14 +5,14 @@
           data: {drag_path: reparent_quantity_path(quantity), drop_id: dom_id(quantity),
                  drop_id_param: "quantity[parent_id]"} do %>

-  <td class="link" style="--depth:<%= quantity.depth %>">
-    <%= link_to quantity, edit_quantity_path(quantity), onclick: 'this.blur();',
-      data: {turbo_stream: true} %>
+  <td style="--depth:<%= quantity.depth %>">
+    <%= link_to quantity, edit_quantity_path(quantity), class: 'link',
+      onclick: 'this.blur();', data: {turbo_stream: true} %>
  </td>
  <td><%= quantity.description %></td>

  <% if current_user.at_least(:active) %>
-    <td class="actions">
+    <td class="flex">
      <%= image_link_to t('.new_subquantity'), 'plus-outline', new_quantity_path(quantity),
        id: dom_id(quantity, :new, :link), onclick: 'this.blur();', data: {turbo_stream: true} %>

--- a/app/views/quantities/index.html.erb
+++ b/app/views/quantities/index.html.erb
@@ -8,13 +8,14 @@
    class: 'tools-area' %>
 </div>

+<%# TODO: remove? form can be inserted directly, e.g. at the end of index %>
 <%= tag.div class: 'main-area', id: :quantity_form %>

-<table class="main-area items">
+<table class="main-area items-table">
  <thead>
    <tr>
      <th><%= Quantity.human_attribute_name(:name) %></th>
-      <th><%= Quantity.human_attribute_name(:description) %></th>
+      <th class="hexpand"><%= Quantity.human_attribute_name(:description) %></th>
      <% if current_user.at_least(:active) %>
        <th><%= t :actions %></th>
        <th></th>
--- a/app/views/readouts/_form.html.erb
+++ b/app/views/readouts/_form.html.erb
@@ -1,25 +1,24 @@
 <%# TODO: add readout reordering by dragging %>
 <%= tabular_fields_for 'readouts[]', readout do |form| %>
  <%- tag.tr id: dom_id(readout.quantity, :new, :readout) do %>
-    <td class="actions">
+    <td>
+      <%# TODO: add grayed readout index (in separate column?) %>
+      <%= readout.quantity.relative_pathname(@superquantity) %>
+      <%= form.hidden_field :quantity_id %>
+    </td>
+    <td>
+      <%= form.number_field :value, required: true, autofocus: readout_counter == 0 %>
+    </td>
+    <td>
+      <%= form.collection_select :unit_id, @user_units, :id,
+        ->(u){ sanitize('&emsp;' * (u.base_id ? 1 : 0) + u.symbol) },
+        {prompt: '', disabled: '', selected: ''}, required: true %>
+    </td>
+    <td class="flex">
      <%# TODO: change to _link_ after giving up displaying relative paths %>
      <%= image_button_tag '', 'delete-outline', class: 'dangerous', name: nil,
        formaction: discard_readouts_path(readout.quantity),
        formmethod: :get, formnovalidate: true, data: {turbo_stream: true} %>
    </td>
-    <td>
-      <%= readout.quantity.relative_pathname(@superquantity) %>
-    </td>
-    <td>
-      <%= form.number_field :value, required: true,
-        size: readout.type_for_attribute(:value).precision / 2,
-        autofocus: readout_counter == 0 %>
-    </td>
-    <td>
-      <%= form.hidden_field :quantity_id %>
-      <%= form.collection_select :unit_id, @user_units, :id,
-        ->(u){ sanitize('&emsp;' * (u.base_id ? 1 : 0) + u.symbol) },
-        {prompt: t('.select_unit'), disabled: '', selected: ''}, required: true %>
-    </td>
  <% end %>
 <% end %>
--- a/app/views/units/_form.html.erb
+++ b/app/views/units/_form.html.erb
@@ -8,11 +8,11 @@
    <td>
      <%= form.text_area :description, cols: 30, rows: 1, escape: false %>
    </td>
-    <td class="number">
-      <%= form.number_field :multiplier, required: true, size: 10, min: :step if @unit.base_id? %>
+    <td>
+      <%= form.number_field :multiplier, required: true if @unit.base_id? %>
    </td>

-    <td class="actions">
+    <td class="flex">
      <%= form.button %>
      <%= image_link_to t(:cancel), "close-outline", units_path, class: 'dangerous',
        name: :cancel, onclick: render_turbo_stream('form_close', {row: row}) %>
--- a/app/views/units/_unit.html.erb
+++ b/app/views/units/_unit.html.erb
@@ -6,14 +6,15 @@
                  drop_id: dom_id(unit.base || unit),
                  drop_id_param: "unit[base_id]"} do %>

-  <td class="link" style="--depth:<%= unit.base_id? ? 1 : 0 %>">
-    <%= link_to unit, edit_unit_path(unit), onclick: 'this.blur();', data: {turbo_stream: true} %>
+  <td style="--depth:<%= unit.base_id? ? 1 : 0 %>">
+    <%= link_to unit, edit_unit_path(unit), class: 'link', onclick: 'this.blur();',
+      data: {turbo_stream: true} %>
  </td>
  <td><%= unit.description %></td>
-  <td class="number"><%= unit.multiplier.to_html %></td>
+  <td class="ralign"><%= unit.multiplier.to_html if unit.base_id? %></td>

  <% if current_user.at_least(:active) %>
-    <td class="actions">
+    <td class="flex">
      <% unless unit.base_id? %>
        <%= image_link_to t('.new_subunit'), 'plus-outline', new_unit_path(unit),
          id: dom_id(unit, :new, :link), onclick: 'this.blur();', data: {turbo_stream: true} %>
--- a/app/views/units/index.html.erb
+++ b/app/views/units/index.html.erb
@@ -7,13 +7,14 @@
    class: 'tools-area' %>
 </div>

+<%# TODO: remove? form can be inserted directly, e.g. at the end of index %>
 <%= tag.div id: :unit_form %>

-<table class="main-area items">
+<table class="main-area items-table">
  <thead>
    <tr>
      <th><%= Unit.human_attribute_name(:symbol) %></th>
-      <th><%= Unit.human_attribute_name(:description) %></th>
+      <th class="hexpand"><%= Unit.human_attribute_name(:description) %></th>
      <th><%= Unit.human_attribute_name(:multiplier) %></th>
      <% if current_user.at_least(:active) %>
        <th><%= t :actions %></th>
--- a/app/views/units/rebase.turbo_stream.erb
+++ b/app/views/units/rebase.turbo_stream.erb
@@ -1,4 +1,4 @@
 <%= turbo_stream.remove @unit %>
 <%= turbo_stream.replace @previous_base if @previous_base %>
-<%= turbo_stream.replace @unit.base if @unit.base_id? && (@previous_base.id != @unit.base_id) %>
+<%= turbo_stream.replace @unit.base if @unit.base_id? && (@previous_base&.id != @unit.base_id) %>
 <%= @before ? turbo_stream.before(@before, @unit) : turbo_stream.append(:units, @unit) %>
--- a/app/views/users/index.html.erb
+++ b/app/views/users/index.html.erb
@@ -1,4 +1,4 @@
-<table class="main-area items" id="users">
+<table class="main-area items-table" id="users">
  <thead>
    <tr>
      <th><%= User.human_attribute_name(:email) %></th>
@@ -11,7 +11,7 @@
  <tbody>
    <% @users.each do |user| %>
      <tr>
-        <td class="link"><%= link_to user, user_path(user) %></td>
+        <td><%= link_to user, user_path(user), class: 'link' %></td>
        <td>
          <% if user == current_user %>
            <%= user.status %>
@@ -22,11 +22,11 @@
            <% end %>
          <% end %>
        </td>
-        <td class="svg">
+        <td>
          <%= svg_tag 'pictograms/checkbox-marked-outline' if user.confirmed_at.present? %>
        </td>
        <td><%= l user.created_at, format: :without_tz %></td>
-        <td class="actions">
+        <td class="flex">
          <% if allow_disguise?(user) %>
            <%= image_link_to t('.disguise'), 'incognito', disguise_user_path(user) %>
          <% end %>
--- a/app/views/users/profiles/new.html.erb
+++ b/app/views/users/profiles/new.html.erb
@@ -10,7 +10,6 @@

  <%= f.submit t(:register), data: {turbo: false} %>

-  <%# TODO: fix button text color after change link -> button %>
  <%= image_button_tag t(:resend_confirmation), 'email-sync-outline',
    class: 'auxiliary', formaction: user_confirmation_path, formnovalidate: true,
    data: {validate: f.field_id(:email)} %>
--- a/app/views/users/unlocks/new.html.erb
+++ b/app/views/users/unlocks/new.html.erb
@@ -8,7 +8,7 @@
    <%= f.email_field :email, autofocus: true, autocomplete: "email" %>
  </div>

-  <div class="actions">
+  <div class="flex">
    <%= f.submit "Resend unlock instructions" %>
  </div>
 <% end %>
--- a/bin/ci
+++ b/bin/ci
@@ -0,0 +1,6 @@
+#!/usr/bin/env ruby
+require_relative "../config/boot"
+require "active_support/continuous_integration"
+
+CI = ActiveSupport::ContinuousIntegration
+require_relative "../config/ci.rb"
--- a/bin/dev
+++ b/bin/dev
@@ -0,0 +1,2 @@
+#!/usr/bin/env ruby
+exec "./bin/rails", "server", *ARGV
--- a/bin/fixinme.service.dist
+++ b/bin/fixinme.service.dist
--- a/bin/setup
+++ b/bin/setup
@@ -1,11 +1,10 @@
 #!/usr/bin/env ruby
 require "fileutils"

-# path to your application root.
 APP_ROOT = File.expand_path("..", __dir__)

 def system!(*args)
-  system(*args) || abort("\n== Command #{args} failed ==")
+  system(*args, exception: true)
 end

 FileUtils.chdir APP_ROOT do
@@ -14,7 +13,6 @@ FileUtils.chdir APP_ROOT do
  # Add necessary setup steps to this file.

  puts "== Installing dependencies =="
-  system! "gem install bundler --conservative"
  system("bundle check") || system!("bundle install")

  # puts "\n== Copying sample files =="
@@ -24,10 +22,14 @@ FileUtils.chdir APP_ROOT do

  puts "\n== Preparing database =="
  system! "bin/rails db:prepare"
+  system! "bin/rails db:reset" if ARGV.include?("--reset")

  puts "\n== Removing old logs and tempfiles =="
  system! "bin/rails log:clear tmp:clear"

-  puts "\n== Restarting application server =="
-  system! "bin/rails restart"
+  unless ARGV.include?("--skip-server")
+    puts "\n== Starting development server =="
+    STDOUT.flush # flush the output before exec(2) so that it displays
+    exec "bin/dev"
+  end
 end
--- a/config/application.rb.dist
+++ b/config/application.rb.dist
@@ -18,14 +18,17 @@ require "rails/test_unit/railtie"
 # you've limited to :test, :development, or :production.
 Bundler.require(*Rails.groups)

+require_relative '../lib/default_settings_strategy'
+
 module FixinMe
  class Application < Rails::Application
    # Initialize configuration defaults for originally generated Rails version.
-    config.load_defaults 7.0
+    config.load_defaults 8.1

-    # Autoload lib/, required e.g. for core library extensions.
-    # https://guides.rubyonrails.org/autoloading_and_reloading_constants.html#config-autoload-lib-ignore.
-    config.autoload_lib(ignore: %w(assets tasks))
+    # Please, add to the `ignore` list any other `lib` subdirectories that do
+    # not contain `.rb` files, or that should not be reloaded or eager loaded.
+    # Common ones are `templates`, `generators`, or `middleware`, for example.
+    config.autoload_lib(ignore: %w[assets tasks])

    # Configuration for the application, engines, and railties goes here.
    #
@@ -38,16 +41,19 @@ module FixinMe
    config.action_dispatch.rescue_responses['ApplicationController::AccessForbidden'] = :forbidden
    config.action_dispatch.rescue_responses['ApplicationController::ParameterInvalid'] = :unprocessable_entity

+    # Set default migrations parameters.
+    config.active_record.migration_strategy = DefaultSettingsStrategy
+
    # SETUP: Below settings need to be updated on a per-installation basis.
    #
-    # URL to use in sent e-mails.
-    config.action_mailer.default_url_options = {host: 'localhost', :protocol => 'https'}
+    # Set host to be used by links generated in mailer templates.
+    config.action_mailer.default_url_options = {host: 'localhost', protocol: 'https'}
    # https://guides.rubyonrails.org/configuring.html#config-action-mailer-delivery-method
    config.action_mailer.delivery_method = :sendmail

    # List of hosts this app is available at.
    # https://guides.rubyonrails.org/configuring.html#actiondispatch-hostauthorization
-    config.hosts += ['localhost', 'example.com', IPAddr.new('1.2.3.4/32')]
+    config.hosts |= ['localhost']

    # Email address of admin account
    config.admin = 'admin@localhost'
--- a/config/ci.rb
+++ b/config/ci.rb
@@ -0,0 +1,20 @@
+# Run using bin/ci
+
+CI.run do
+  step "Setup", "bin/setup --skip-server"
+
+  step "Security: Importmap vulnerability audit", "bin/importmap audit"
+  step "Tests: Rails", "bin/rails test"
+  step "Tests: Seeds", "env RAILS_ENV=test bin/rails db:seed:replant"
+
+  # Optional: Run system tests
+  # step "Tests: System", "bin/rails test:system"
+
+  # Optional: set a green GitHub commit status to unblock PR merge.
+  # Requires the `gh` CLI and `gh extension install basecamp/gh-signoff`.
+  # if success?
+  #   step "Signoff: All systems go. Ready for merge and deploy.", "gh signoff"
+  # else
+  #   failure "Signoff: CI failed. Do not merge or deploy.", "Fix the issues and try again."
+  # end
+end
--- a/config/database.yml.dist
+++ b/config/database.yml.dist
@@ -24,27 +24,45 @@
 # Read https://guides.rubyonrails.org/configuring.html#configuring-a-database
 # for a full overview on how database connection configuration can be specified.
 default: &default
-  adapter: mysql2
-  encoding: utf8mb4
-  collation: utf8mb4_0900_as_ci
-  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
-  username: fixinme
-  password: Some-password1%
-  socket: /run/mysqld/mysqld.sock
+  pool: <%= ENV.fetch('RAILS_MAX_THREADS', 3) %>
+
+#mysql_default: &mysql_default
+#  <<: *default
+#  username: fixinme
+#  password: Some-password1%
+#  host: 127.0.0.1
+#  encoding: utf8mb4
+#  collation: utf8mb4_0900_as_ci

 production:
  <<: *default
-  database: fixinme
+  adapter: sqlite3
+  database: db/production.sqlite3

-# Unless you're planning on developing the application, you can skip
+# Unless you're planning on developing the application, you can skip/remove
 # configurations for development and test databases altogether.
 #development:
-#  <<: *default
+#  <<: *mysql_default
+#  adapter: mysql2
 #  database: fixinme_dev

-# Warning: The database defined as "test" will be erased and
+# Warning: The database(s) defined as "test" will be erased and
 # re-generated from your development database when you run "rake".
 # Do not set this db to the same as development or production.
 #test:
-#  <<: *default
+#  <<: *mysql_default
+#  adapter: mysql2
 #  database: fixinme_test
+
+# Multiple test databases can be provided. When more than one test db is
+# present, every test task (test, test:models, test:system, etc.) runs against
+# all of them.
+#test:
+#  mysql2:
+#    <<: *mysql_default
+#    adapter: mysql2
+#    database: fixinme_test
+#  sqlite3:
+#    <<: *default
+#    adapter: sqlite3
+#    database: db/test.sqlite3
--- a/config/environments/development.rb
+++ b/config/environments/development.rb
@@ -3,10 +3,8 @@ require "active_support/core_ext/integer/time"
 Rails.application.configure do
  # Settings specified here will take precedence over those in config/application.rb.

-  # In the development environment your application's code is reloaded any time
-  # it changes. This slows down response time but is perfect for development
-  # since you don't have to restart the web server when you make code changes.
-  config.cache_classes = false
+  # Make code changes take effect immediately without server restart.
+  config.enable_reloading = true

  # Do not eager load code on boot.
  config.eager_load = false
@@ -14,54 +12,52 @@ Rails.application.configure do
  # Show full error reports.
  config.consider_all_requests_local = true

-  # Enable server timing
+  # Enable server timing.
  config.server_timing = true

-  # Enable/disable caching. By default caching is disabled.
-  # Run rails dev:cache to toggle caching.
+  # Enable/disable Action Controller caching. By default Action Controller caching is disabled.
+  # Run rails dev:cache to toggle Action Controller caching.
  if Rails.root.join("tmp/caching-dev.txt").exist?
    config.action_controller.perform_caching = true
    config.action_controller.enable_fragment_cache_logging = true
-
-    config.cache_store = :memory_store
-    config.public_file_server.headers = {
-      "Cache-Control" => "public, max-age=#{2.days.to_i}"
-    }
+    config.public_file_server.headers = { "cache-control" => "public, max-age=#{2.days.to_i}" }
  else
    config.action_controller.perform_caching = false
-
-    config.cache_store = :null_store
  end

+  # Change to :null_store to avoid any caching.
+  config.cache_store = :memory_store
+
  # Don't care if the mailer can't send.
  config.action_mailer.raise_delivery_errors = false

+  # Make template changes take effect immediately.
  config.action_mailer.perform_caching = false

  # Print deprecation notices to the Rails logger.
  config.active_support.deprecation = :log

-  # Raise exceptions for disallowed deprecations.
-  config.active_support.disallowed_deprecation = :raise
-
-  # Tell Active Support which deprecation messages to disallow.
-  config.active_support.disallowed_deprecation_warnings = []
-
  # Raise an error on page load if there are pending migrations.
  config.active_record.migration_error = :page_load

  # Highlight code that triggered database queries in logs.
  config.active_record.verbose_query_logs = true

-  # Suppress logger output for asset requests.
-  config.assets.quiet = true
+  # Append comments with runtime information tags to SQL queries in logs.
+  config.active_record.query_log_tags_enabled = true
+
+  # Highlight code that enqueued background job in logs.
+  config.active_job.verbose_enqueue_logs = true
+
+  # Highlight code that triggered redirect in logs.
+  config.action_dispatch.verbose_redirect_logs = true

  # Raises error for missing translations.
  # config.i18n.raise_on_missing_translations = true

  # Annotate rendered view with file names.
-  # config.action_view.annotate_rendered_view_with_filenames = true
+  config.action_view.annotate_rendered_view_with_filenames = true

-  # Uncomment if you wish to allow Action Cable access from any origin.
-  # config.action_cable.disable_request_forgery_protection = true
+  # Raise error when a before_action's only/except options reference missing actions.
+  config.action_controller.raise_on_missing_callback_actions = true
 end
--- a/config/environments/production.rb
+++ b/config/environments/production.rb
@@ -4,78 +4,83 @@ Rails.application.configure do
  # Settings specified here will take precedence over those in config/application.rb.

  # Code is not reloaded between requests.
-  config.cache_classes = true
+  config.enable_reloading = false

-  # Eager load code on boot. This eager loads most of Rails and
-  # your application in memory, allowing both threaded web servers
-  # and those relying on copy on write to perform better.
-  # Rake tasks automatically ignore this option for performance.
+  # Eager load code on boot for better performance and memory savings (ignored by Rake tasks).
  config.eager_load = true

-  # Full error reports are disabled and caching is turned on.
-  config.consider_all_requests_local       = false
+  # Full error reports are disabled.
+  config.consider_all_requests_local = false
+
+  # Turn on fragment caching in view templates.
  config.action_controller.perform_caching = true

-  # Ensures that a master key has been made available in either ENV["RAILS_MASTER_KEY"]
-  # or in config/master.key. This key is used to decrypt credentials (and other encrypted files).
-  # config.require_master_key = true
-
-  # Disable serving static files from the `/public` folder by default since
-  # Apache or NGINX already handles this.
-  config.public_file_server.enabled = ENV["RAILS_SERVE_STATIC_FILES"].present?
-
-  # Compress CSS using a preprocessor.
-  # config.assets.css_compressor = :sass
-
-  # Do not fallback to assets pipeline if a precompiled asset is missed.
-  config.assets.compile = false
+  # Cache assets for far-future expiry since they are all digest stamped.
+  config.public_file_server.headers = { "cache-control" => "public, max-age=#{1.year.to_i}" }

  # Enable serving of images, stylesheets, and JavaScripts from an asset server.
  # config.asset_host = "http://assets.example.com"

-  # Specifies the header that your server uses for sending files.
-  # config.action_dispatch.x_sendfile_header = "X-Sendfile" # for Apache
-  # config.action_dispatch.x_sendfile_header = "X-Accel-Redirect" # for NGINX
+  # Assume all access to the app is happening through a SSL-terminating reverse proxy.
+  config.assume_ssl = true

  # Force all access to the app over SSL, use Strict-Transport-Security, and use secure cookies.
-  # config.force_ssl = true
+  config.force_ssl = true

-  # Include generic and useful information about system operation, but avoid logging too much
-  # information to avoid inadvertent exposure of personally identifiable information (PII).
-  config.log_level = :info
+  # Skip http-to-https redirect for the default health check endpoint.
+  # config.ssl_options = { redirect: { exclude: ->(request) { request.path == "/up" } } }

-  # Prepend all log lines with the following tags.
+  # Log to STDOUT with the current request id as a default log tag.
  config.log_tags = [ :request_id ]
+  config.logger   = ActiveSupport::TaggedLogging.logger(STDOUT)

-  # Use a different cache store in production.
+  # Change to "debug" to log everything (including potentially personally-identifiable information!).
+  config.log_level = ENV.fetch("RAILS_LOG_LEVEL", "info")
+
+  # Prevent health checks from clogging up the logs.
+  config.silence_healthcheck_path = "/up"
+
+  # Don't log any deprecations.
+  config.active_support.report_deprecations = false
+
+  # Replace the default in-process memory cache store with a durable alternative.
  # config.cache_store = :mem_cache_store

-  config.action_mailer.perform_caching = false
+  # Replace the default in-process and non-durable queuing backend for Active Job.
+  # config.active_job.queue_adapter = :resque

  # Ignore bad email addresses and do not raise email delivery errors.
  # Set this to true and configure the email server for immediate delivery to raise delivery errors.
  # config.action_mailer.raise_delivery_errors = false

+  # Specify outgoing SMTP server. Remember to add smtp/* credentials via bin/rails credentials:edit.
+  # config.action_mailer.smtp_settings = {
+  #   user_name: Rails.application.credentials.dig(:smtp, :user_name),
+  #   password: Rails.application.credentials.dig(:smtp, :password),
+  #   address: "smtp.example.com",
+  #   port: 587,
+  #   authentication: :plain
+  # }
+
  # Enable locale fallbacks for I18n (makes lookups for any locale fall back to
  # the I18n.default_locale when a translation cannot be found).
  config.i18n.fallbacks = true

-  # Don't log any deprecations.
-  config.active_support.report_deprecations = false
-
-  # Use default logging formatter so that PID and timestamp are not suppressed.
-  config.log_formatter = ::Logger::Formatter.new
-
-  # Use a different logger for distributed setups.
-  # require "syslog/logger"
-  # config.logger = ActiveSupport::TaggedLogging.new(Syslog::Logger.new "app-name")
-
-  if ENV["RAILS_LOG_TO_STDOUT"].present?
-    logger           = ActiveSupport::Logger.new(STDOUT)
-    logger.formatter = config.log_formatter
-    config.logger    = ActiveSupport::TaggedLogging.new(logger)
-  end
-
  # Do not dump schema after migrations.
  config.active_record.dump_schema_after_migration = false
+
+  # Only use :id for inspections in production.
+  config.active_record.attributes_for_inspect = [ :id ]
+
+  # Enable DNS rebinding protection and other `Host` header attacks.
+  # config.hosts = [
+  #   "example.com",     # Allow requests from example.com
+  #   /.*\.example\.com/ # Allow requests from subdomains like `www.example.com`
+  # ]
+  #
+  # Skip DNS rebinding protection for the default health check endpoint.
+  # config.host_authorization = { exclude: ->(request) { request.path == "/up" } }
+
+  # Protect e-mail addresses from being logged only in production.
+  config.filter_parameters += [:email]
 end
--- a/config/environments/test.rb
+++ b/config/environments/test.rb
@@ -1,5 +1,3 @@
-require "active_support/core_ext/integer/time"
-
 # The test environment is used exclusively to run your application's
 # test suite. You never need to work with it otherwise. Remember that
 # your test database is "scratch space" for the test suite and is wiped
@@ -8,57 +6,49 @@ require "active_support/core_ext/integer/time"
 Rails.application.configure do
  # Settings specified here will take precedence over those in config/application.rb.

-  # Turn false under Spring and add config.action_view.cache_template_loading = true.
-  config.cache_classes = true
+  # While tests run files are not watched, reloading is not necessary.
+  config.enable_reloading = false

-  # Eager loading loads your whole application. When running a single test locally,
-  # this probably isn't necessary. It's a good idea to do in a continuous integration
-  # system, or in some way before deploying your code.
+  # Eager loading loads your entire application. When running a single test locally,
+  # this is usually not necessary, and can slow down your test suite. However, it's
+  # recommended that you enable it in continuous integration systems to ensure eager
+  # loading is working properly before deploying your code.
  config.eager_load = ENV["CI"].present?

-  # Configure public file server for tests with Cache-Control for performance.
-  config.public_file_server.enabled = true
-  config.public_file_server.headers = {
-    "Cache-Control" => "public, max-age=#{1.hour.to_i}"
-  }
+  # Configure public file server for tests with cache-control for performance.
+  config.public_file_server.headers = { "cache-control" => "public, max-age=3600" }

-  # Hide full error reports.
-  config.consider_all_requests_local     = false
-  # Render exception templates instead of raising exceptions.
-  config.action_dispatch.show_exceptions = :all
+  # Behave as in `production`.
+  config.consider_all_requests_local = false

-  # Disable caching.
-  config.action_controller.perform_caching = false
  config.cache_store = :null_store

  # Disable request forgery protection in test environment.
  config.action_controller.allow_forgery_protection = false

-  config.action_mailer.perform_caching = false
-
  # Tell Action Mailer not to deliver emails to the real world.
  # The :test delivery method accumulates sent emails in the
  # ActionMailer::Base.deliveries array.
  config.action_mailer.delivery_method = :test
-  config.action_mailer.default_url_options = {host: '127.0.0.1', :protocol => 'http'}
+
+  # Set host to be used by links generated in mailer templates.
+  config.action_mailer.default_url_options = {host: Capybara.server_host,
+                                              protocol: 'http'}

  # Print deprecation notices to the stderr.
  config.active_support.deprecation = :stderr

-  # Raise exceptions for disallowed deprecations.
-  config.active_support.disallowed_deprecation = :raise
-
-  # Tell Active Support which deprecation messages to disallow.
-  config.active_support.disallowed_deprecation_warnings = []
-
  # Raises error for missing translations.
  config.i18n.raise_on_missing_translations = true

  # Annotate rendered view with file names.
  # config.action_view.annotate_rendered_view_with_filenames = true

-  config.log_level = :info
+  # Raise error when a before_action's only/except options reference missing actions.
+  config.action_controller.raise_on_missing_callback_actions = true

-  # Allow the default integration test host.
-  config.hosts << "www.example.com"
+  # Allow Capybara application server IP
+  config.hosts |= [IPAddr.new(Capybara.server_host)]
+
+  config.log_level = :info
 end
--- a/config/initializers/assets.rb
+++ b/config/initializers/assets.rb
@@ -5,8 +5,3 @@ Rails.application.config.assets.version = "1.0"

 # Add additional assets to the asset load path.
 # Rails.application.config.assets.paths << Emoji.images_path
-
-# Precompile additional assets.
-# application.js, application.css, and all non-JS/CSS in the app/assets
-# folder are already added.
-Rails.application.config.assets.precompile += %w( '*.svg' )
--- a/config/initializers/content_security_policy.rb
+++ b/config/initializers/content_security_policy.rb
@@ -16,9 +16,13 @@
 #     # policy.report_uri "/csp-violation-report-endpoint"
 #   end
 #
-#   # Generate session nonces for permitted importmap and inline scripts
+#   # Generate session nonces for permitted importmap, inline scripts, and inline styles.
 #   config.content_security_policy_nonce_generator = ->(request) { request.session.id.to_s }
-#   config.content_security_policy_nonce_directives = %w(script-src)
+#   config.content_security_policy_nonce_directives = %w(script-src style-src)
+#
+#   # Automatically add `nonce` to `javascript_tag`, `javascript_include_tag`, and `stylesheet_link_tag`
+#   # if the corresponding directives are specified in `content_security_policy_nonce_directives`.
+#   # config.content_security_policy_nonce_auto = true
 #
 #   # Report violations without enforcing the policy.
 #   # config.content_security_policy_report_only = true
--- a/config/initializers/core_ext.rb
+++ b/config/initializers/core_ext.rb
@@ -1,5 +1,6 @@
 require 'core_ext/array_delete_bang'
-require 'core_ext/big_decimal_scientific_notation'
+require 'core_ext/float'
+require 'core_ext/range'

 ActiveSupport.on_load :action_dispatch_system_test_case do
  prepend CoreExt::ActionDispatch::SystemTesting::TestHelpers::ScreenshotHelperUniqueId
@@ -10,9 +11,6 @@ ActiveSupport.on_load :action_view do
 end

 ActiveSupport.on_load :active_record do
-  ActiveModel::Validations::NumericalityValidator
-    .prepend CoreExt::ActiveModel::Validations::NumericalityValidatesPrecisionAndScale
-
  # Temporary patch for https://github.com/rails/rails/pull/54658
  Arel::TreeManager::StatementMethods
    .prepend CoreExt::Arel::TreeManager::StatementMethodsCteUpdateAndDelete
--- a/config/initializers/devise.rb
+++ b/config/initializers/devise.rb
@@ -179,7 +179,7 @@ Devise.setup do |config|

  # ==> Configuration for :validatable
  # Range for password length.
-  config.password_length = 5..128
+  config.password_length = 5..32

  # Email regex used to validate email formats. It simply asserts that
  # one (and only one) @ exists in the given string. This is mainly
--- a/config/initializers/filter_parameter_logging.rb
+++ b/config/initializers/filter_parameter_logging.rb
@@ -1,8 +1,8 @@
 # Be sure to restart your server when you modify this file.

-# Configure parameters to be filtered from the log file. Use this to limit dissemination of
-# sensitive information. See the ActiveSupport::ParameterFilter documentation for supported
-# notations and behaviors.
+# Configure parameters to be partially matched (e.g. passw matches password) and filtered from the log file.
+# Use this to limit dissemination of sensitive information.
+# See the ActiveSupport::ParameterFilter documentation for supported notations and behaviors.
 Rails.application.config.filter_parameters += [
-  :passw, :secret, :token, :_key, :crypt, :salt, :certificate, :otp, :ssn
+  :passw, :secret, :token, :_key, :crypt, :salt, :certificate, :otp, :ssn, :cvv, :cvc
 ]
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -4,10 +4,6 @@ en:
      # Format contains non-breaking space: 160.chr(Encoding::UTF_8)
      default: "%Y-%m-%d %H:%M %Z"
      without_tz: "%Y-%m-%d %H:%M"
-  errors:
-    messages:
-      precision_exceeded: must not exceed %{value} significant digits
-      scale_exceeded: must not exceed %{value} decimal digits
  activerecord:
    attributes:
      quantity:
@@ -85,12 +81,10 @@ en:
    navigation: Measurements
    no_items: There are no measurements taken. You can Add some now.
    form:
-      select_quantity: select the measured quantities...
+      select_quantity: select quantities...
+      taken_at_html: Measurement taken at&emsp;
    index:
      new_measurement: Add measurement
-  readouts:
-    form:
-      select_unit: ...
  quantities:
    navigation: Quantities
    no_items: There are no configured quantities. You can Add some or Import from defaults.
--- a/config/puma.rb.dist
+++ b/config/puma.rb.dist
@@ -1,43 +1,41 @@
-# Puma can serve each request in a thread from an internal thread pool.
-# The `threads` method setting takes two numbers: a minimum and maximum.
-# Any libraries that use thread pools should be configured to match
-# the maximum value specified for Puma. Default is set to 5 threads for minimum
-# and maximum; this matches the default thread size of Active Record.
+# This configuration file will be evaluated by Puma. The top-level methods that
+# are invoked here are part of Puma's configuration DSL. For more information
+# about methods provided by the DSL, see https://puma.io/puma/Puma/DSL.html.
 #
-max_threads_count = ENV.fetch("RAILS_MAX_THREADS") { 5 }
-min_threads_count = ENV.fetch("RAILS_MIN_THREADS") { max_threads_count }
-threads min_threads_count, max_threads_count
-
-# Specifies the `worker_timeout` threshold that Puma will use to wait before
-# terminating a worker in development environments.
+# Puma starts a configurable number of processes (workers) and each process
+# serves each request in a thread from an internal thread pool.
 #
-worker_timeout 3600 if ENV.fetch("RAILS_ENV", "development") == "development"
+# You can control the number of workers using ENV["WEB_CONCURRENCY"]. You
+# should only set this value when you want to run 2 or more workers. The
+# default is already 1.
+#
+# The ideal number of threads per worker depends both on how much time the
+# application spends waiting for IO operations and on how much you wish to
+# prioritize throughput over latency.
+#
+# As a rule of thumb, increasing the number of threads will increase how much
+# traffic a given process can handle (throughput), but due to CRuby's
+# Global VM Lock (GVL) it has diminishing returns and will degrade the
+# response time (latency) of the application.
+#
+# The default is set to 3 threads as it's deemed a decent compromise between
+# throughput and latency for the average Rails application.
+#
+# Any libraries that use a connection pool or another resource pool should
+# be configured to provide at least as many connections as the number of
+# threads. This includes Active Record's `pool` parameter in `database.yml`.
+threads_count = ENV.fetch("RAILS_MAX_THREADS", 3)
+threads threads_count, threads_count

 # Specifies the `port` that Puma will listen on to receive requests; default is 3000.
-#
-port ENV.fetch("PORT") { 3000 }
-
-# Specifies the `environment` that Puma will run in.
-#
-environment ENV.fetch("RAILS_ENV") { "development" }
-
-# Specifies the `pidfile` that Puma will use.
-pidfile ENV.fetch("PIDFILE") { "tmp/pids/server.pid" }
-
-# Specifies the number of `workers` to boot in clustered mode.
-# Workers are forked web server processes. If using threads and workers together
-# the concurrency of the application would be max `threads` * `workers`.
-# Workers do not work on JRuby or Windows (both of which do not support
-# processes).
-#
-# workers ENV.fetch("WEB_CONCURRENCY") { 2 }
-
-# Use the `preload_app!` method when specifying a `workers` number.
-# This directive tells Puma to first boot the application and load code
-# before forking the application. This takes advantage of Copy On Write
-# process behavior so workers use less memory.
-#
-# preload_app!
+port ENV.fetch("PORT", 3000), '127.0.0.1'

 # Allow puma to be restarted by `bin/rails restart` command.
 plugin :tmp_restart
+
+# Run the Solid Queue supervisor inside of Puma for single-server deployments
+plugin :solid_queue if ENV["SOLID_QUEUE_IN_PUMA"]
+
+# Specify the PID file. Defaults to tmp/pids/server.pid in development.
+# In other environments, only set the PID file if requested.
+pidfile ENV["PIDFILE"] if ENV["PIDFILE"]
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -15,7 +15,10 @@ Rails.application.routes.draw do

  namespace :default do
    resources :units, only: [:index, :destroy] do
-      member { post :import, :export }
+      member {
+        post :import
+        post :export
+      }
      #collection { post :import_all }
    end
  end
--- a/db/migrate/20230309185340_create_users.rb
+++ b/db/migrate/20230309185340_create_users.rb
@@ -1,11 +1,11 @@
-class CreateUsers < ActiveRecord::Migration[7.0]
+class CreateUsers < ActiveRecord::Migration[8.1]
  def change
    create_table :users do |t|
      t.string :email, null: false, limit: 64
      t.integer :status, null: false, default: 0

-      t.timestamps null: false
+      t.timestamps
    end
-    add_index :users, :email, unique: true
+    add_index :users, :email
  end
 end
--- a/db/migrate/20230311220654_add_devise_to_users.rb
+++ b/db/migrate/20230311220654_add_devise_to_users.rb
@@ -1,4 +1,4 @@
-class AddDeviseToUsers < ActiveRecord::Migration[7.0]
+class AddDeviseToUsers < ActiveRecord::Migration[8.1]
  def change
    change_table :users do |t|
      ## NOTE: commented fields left for reference/inclusion in future migrations
@@ -34,8 +34,8 @@ class AddDeviseToUsers < ActiveRecord::Migration[7.0]
      # t.integer :failed_attempts, default: 0, null: false 
    end

-    add_index :users, :reset_password_token, unique: true
-    add_index :users, :confirmation_token, unique: true
+    add_index :users, :reset_password_token
+    add_index :users, :confirmation_token
    # add_index :users, :unlock_token, unique: true
  end
 end
--- a/db/migrate/20230602185352_create_units.rb
+++ b/db/migrate/20230602185352_create_units.rb
@@ -1,14 +1,15 @@
-class CreateUnits < ActiveRecord::Migration[7.0]
+class CreateUnits < ActiveRecord::Migration[8.1]
  def change
    create_table :units do |t|
-      t.references :user, foreign_key: true
+      t.references :user, foreign_key: {on_delete: :cascade}
      t.string :symbol, null: false, limit: 15
      t.text :description
-      t.decimal :multiplier, null: false, precision: 30, scale: 15, default: 1.0
+      t.float :multiplier, null: false, limit: Float::MANT_DIG, default: 1.0
      t.references :base, foreign_key: {to_table: :units, on_delete: :cascade}

-      t.timestamps null: false
+      t.timestamps
    end
-    add_index :units, [:user_id, :symbol], unique: true
+    add_index :units, [:user_id, :symbol]
+    add_index :units, [:id, :user_id]
  end
 end
--- a/db/migrate/20250104194343_create_quantities.rb
+++ b/db/migrate/20250104194343_create_quantities.rb
@@ -1,17 +1,18 @@
-class CreateQuantities < ActiveRecord::Migration[7.2]
+class CreateQuantities < ActiveRecord::Migration[8.1]
  def change
    create_table :quantities do |t|
-      t.references :user, foreign_key: true
+      t.references :user, foreign_key: {on_delete: :cascade}
      t.string :name, null: false, limit: 31
      t.text :description
      t.references :parent, foreign_key: {to_table: :quantities, on_delete: :cascade}

-      t.timestamps null: false
+      t.timestamps

      # Caches; can be computed from other attributes
      t.integer :depth, null: false, default: 0
      t.string :pathname, null: false, limit: 511
    end
-    add_index :quantities, [:user_id, :parent_id, :name], unique: true
+    add_index :quantities, [:user_id, :parent_id, :name]
+    add_index :quantities, [:id, :user_id]
  end
 end
--- a/db/migrate/20250121230456_create_readouts.rb
+++ b/db/migrate/20250121230456_create_readouts.rb
@@ -1,15 +1,69 @@
-class CreateReadouts < ActiveRecord::Migration[7.2]
+class CreateReadouts < ActiveRecord::Migration[8.1]
  def change
-    create_table :readouts do |t|
-      t.references :user, null: false, foreign_key: true
-      t.references :quantity, null: false, foreign_key: true
-      t.references :unit, foreign_key: true
-      t.decimal :value, null: false, precision: 30, scale: 15
+    create_table :notes do |t|
+      t.text :text, null: false
+
+      t.timestamps
+    end
+
+    create_table :measurements do |t|
+      t.datetime :taken_at, null: false
      #t.references :collector, foreign_key: true
      #t.references :device, foreign_key: true
+      t.references :note, foreign_key: {on_delete: :nullify}

-      t.timestamps null: false
+      t.timestamps
    end
-    add_index :readouts, [:quantity_id, :created_at], unique: true
+    add_index :measurements, :taken_at
+
+    # Defining Readouts as a super-/subclass polymorphic relations for different
+    # subclass data types (numeric, string, file) is not possible with proper
+    # referential integrity constraints. The required constraints are:
+    # * for every subclass record to have superclass record,
+    # * for every superclass record to have only one type of subclass record,
+    # * for every superclass record to have subclass record (unenforcable).
+    #   * this can be partially remedied by making superlass an abstract class in
+    #     Rails and disallow direct creation of records, but direct data
+    #     manipulation can still break referential integrity.
+    # Defining separate {Numeric,Text,File}_Readouts tables would make the
+    # unique index constraint unenforcable.
+    create_table :readouts do |t|
+      t.references :user, null: false, foreign_key: {on_delete: :cascade}
+      t.references :measurement, foreign_key: {on_delete: :cascade}
+      t.references :quantity, null: false, foreign_key: {on_delete: :cascade}
+      t.integer :category, null: false, default: 0
+      t.float :value, null: false, limit: Float::MANT_DIG
+      t.references :unit, null: false, foreign_key: {on_delete: :cascade}
+      # TODO: consider additional columns to allow wider range of value types
+      # t.text :text
+      # t.datetime :time
+      # t.references :file
+      # Possibly mutually exclusive with :unit or check constraint for:
+      #   :unit is not null <=> :value is not null
+
+      t.timestamps
+    end
+    add_index :readouts, [:measurement_id, :quantity_id, :category]
+    add_foreign_key :readouts, :quantities, column: [:quantity_id, :user_id],
+      primary_key: [:id, :user_id]
+    add_foreign_key :readouts, :units, column: [:unit_id, :user_id],
+      primary_key: [:id, :user_id]
+
+    # TODO: remove below tables after current setup verified
+    #create_table :numeric_values do |t|
+    #  t.references :readout, null: false, foreign_key: {on_delete: :cascade}
+    #  t.float :value, null: false, limit: Float::MANT_DIG
+    #  t.references :unit, null: false, foreign_key: {on_delete: :cascade}
+    #  # + generated, not stored column :value_type
+    #  # + foreign key constraint to readouts: [:readout_id, :value_id, :value_type]
+    #  # or 2 constraints: [:readout_id, :value_id], [:value_id, :value_type]
+    #  # if readouts.value_id needed, otherwise just one constraint:
+    #  # [:readout_id, :value_type]
+    #end
+
+    #create_table :string_values do |t|
+    #  t.references :readout, null: false, foreign_key: {on_delete: :cascade}
+    #  t.string :value, null: false, limit: 32
+    #end
  end
 end
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,22 @@
 #
 # It's strongly recommended that you check this file into your version control system.

-ActiveRecord::Schema[7.2].define(version: 2025_01_21_230456) do
+ActiveRecord::Schema[8.1].define(version: 2025_01_21_230456) do
+  create_table "measurements", charset: "utf8mb4", collation: "utf8mb4_0900_as_ci", force: :cascade do |t|
+    t.datetime "taken_at", null: false
+    t.bigint "note_id"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["note_id"], name: "index_measurements_on_note_id"
+    t.index ["taken_at"], name: "index_measurements_on_taken_at", unique: true
+  end
+
+  create_table "notes", charset: "utf8mb4", collation: "utf8mb4_0900_as_ci", force: :cascade do |t|
+    t.text "text", null: false
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+  end
+
  create_table "quantities", charset: "utf8mb4", collation: "utf8mb4_0900_as_ci", force: :cascade do |t|
    t.bigint "user_id"
    t.string "name", limit: 31, null: false
@@ -20,6 +35,7 @@ ActiveRecord::Schema[7.2].define(version: 2025_01_21_230456) do
    t.datetime "updated_at", null: false
    t.integer "depth", default: 0, null: false
    t.string "pathname", limit: 511, null: false
+    t.index ["id", "user_id"], name: "index_quantities_on_id_and_user_id", unique: true
    t.index ["parent_id"], name: "index_quantities_on_parent_id"
    t.index ["user_id", "parent_id", "name"], name: "index_quantities_on_user_id_and_parent_id_and_name", unique: true
    t.index ["user_id"], name: "index_quantities_on_user_id"
@@ -27,13 +43,18 @@ ActiveRecord::Schema[7.2].define(version: 2025_01_21_230456) do

  create_table "readouts", charset: "utf8mb4", collation: "utf8mb4_0900_as_ci", force: :cascade do |t|
    t.bigint "user_id", null: false
+    t.bigint "measurement_id"
    t.bigint "quantity_id", null: false
-    t.bigint "unit_id"
-    t.decimal "value", precision: 30, scale: 15, null: false
+    t.integer "category", default: 0, null: false
+    t.float "value", limit: 53, null: false
+    t.bigint "unit_id", null: false
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
-    t.index ["quantity_id", "created_at"], name: "index_readouts_on_quantity_id_and_created_at", unique: true
+    t.index ["measurement_id", "quantity_id", "category"], name: "index_readouts_on_measurement_id_and_quantity_id_and_category", unique: true
+    t.index ["measurement_id"], name: "index_readouts_on_measurement_id"
+    t.index ["quantity_id", "user_id"], name: "fk_rails_9d92eaafc6"
    t.index ["quantity_id"], name: "index_readouts_on_quantity_id"
+    t.index ["unit_id", "user_id"], name: "fk_rails_348b0fb4c5"
    t.index ["unit_id"], name: "index_readouts_on_unit_id"
    t.index ["user_id"], name: "index_readouts_on_user_id"
  end
@@ -42,11 +63,12 @@ ActiveRecord::Schema[7.2].define(version: 2025_01_21_230456) do
    t.bigint "user_id"
    t.string "symbol", limit: 15, null: false
    t.text "description"
-    t.decimal "multiplier", precision: 30, scale: 15, default: "1.0", null: false
+    t.float "multiplier", limit: 53, default: 1.0, null: false
    t.bigint "base_id"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.index ["base_id"], name: "index_units_on_base_id"
+    t.index ["id", "user_id"], name: "index_units_on_id_and_user_id", unique: true
    t.index ["user_id", "symbol"], name: "index_units_on_user_id_and_symbol", unique: true
    t.index ["user_id"], name: "index_units_on_user_id"
  end
@@ -69,11 +91,15 @@ ActiveRecord::Schema[7.2].define(version: 2025_01_21_230456) do
    t.index ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
  end

+  add_foreign_key "measurements", "notes", on_delete: :nullify
  add_foreign_key "quantities", "quantities", column: "parent_id", on_delete: :cascade
-  add_foreign_key "quantities", "users"
-  add_foreign_key "readouts", "quantities"
-  add_foreign_key "readouts", "units"
-  add_foreign_key "readouts", "users"
+  add_foreign_key "quantities", "users", on_delete: :cascade
+  add_foreign_key "readouts", "measurements", on_delete: :cascade
+  add_foreign_key "readouts", "quantities", column: ["quantity_id", "user_id"], primary_key: ["id", "user_id"]
+  add_foreign_key "readouts", "quantities", on_delete: :cascade
+  add_foreign_key "readouts", "units", column: ["unit_id", "user_id"], primary_key: ["id", "user_id"]
+  add_foreign_key "readouts", "units", on_delete: :cascade
+  add_foreign_key "readouts", "users", on_delete: :cascade
  add_foreign_key "units", "units", column: "base_id", on_delete: :cascade
-  add_foreign_key "units", "users"
+  add_foreign_key "units", "users", on_delete: :cascade
 end
--- a/db/seeds.rb
+++ b/db/seeds.rb
@@ -7,17 +7,21 @@
 User.transaction do
  break if User.find_by status: :admin

-  User.create! email: Rails.configuration.admin, password: 'admin', status: :admin do |user|
+  email = Rails.configuration.admin
+  password_length = SecureRandom.rand(Rails.configuration.devise.password_length)
+  password = SecureRandom.alphanumeric(password_length)
+
+  User.create!(email: email, password: password, status: :admin) do |user|
    user.skip_confirmation!
-    print "Creating #{user.status} account '#{user.email}' with password '#{user.password}'..."
+    print "Creating #{user.status} account '#{user.email}'" \
+      " with password '#{user.password}'..."
  end
  puts "done."
-
 rescue ActiveRecord::RecordInvalid => exception
-  puts "failed. #{exception.message}"
+  puts "failed.", exception.message
 end

 # Formulas will be deleted as dependent on Quantities
 #[Source, Quantity, Unit].each { |model| model.defaults.delete_all }

-require_relative 'seeds/units.rb'
+load "db/seeds/units.rb"
--- a/db/seeds/templates/units.erb
+++ b/db/seeds/templates/units.erb
@@ -4,7 +4,7 @@ Unit.transaction do
 <% Unit.defaults.ordered.each do |unit| %>
 <%= "\n" if unit.base.nil? %>
  units['<%= unit.symbol %>'] =
-    Unit.create symbol: '<%= unit.symbol %>',<% unless unit.base.nil? %> base: units['<%= unit.base.symbol %>'], multiplier: '<%= unit.multiplier.to_scientific %>',<% end %>
+    Unit.create symbol: '<%= unit.symbol %>',<% if unit.base_id? %> base: units['<%= unit.base.symbol %>'], multiplier: '<%= unit.multiplier.to_scientific %>',<% end %>
                description: '<%= unit.description %>'
 <% end %>
 end
--- a/db/sqlite3_schema.rb
+++ b/db/sqlite3_schema.rb
@@ -0,0 +1,103 @@
+# This file is auto-generated from the current state of the database. Instead
+# of editing this file, please use the migrations feature of Active Record to
+# incrementally modify your database, and then regenerate this schema definition.
+#
+# This file is the source Rails uses to define your schema when running `bin/rails
+# db:schema:load`. When creating a new database, `bin/rails db:schema:load` tends to
+# be faster and is potentially less error prone than running all of your
+# migrations from scratch. Old migrations may fail to apply correctly if those
+# migrations use external dependencies or application code.
+#
+# It's strongly recommended that you check this file into your version control system.
+
+ActiveRecord::Schema[8.1].define(version: 2025_01_21_230456) do
+  create_table "measurements", force: :cascade do |t|
+    t.datetime "taken_at", null: false
+    t.integer "note_id"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["note_id"], name: "index_measurements_on_note_id"
+    t.index ["taken_at"], name: "index_measurements_on_taken_at", unique: true
+  end
+
+  create_table "notes", force: :cascade do |t|
+    t.text "text", limit: 65535, null: false
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+  end
+
+  create_table "quantities", force: :cascade do |t|
+    t.integer "user_id"
+    t.string "name", limit: 31, null: false
+    t.text "description", limit: 65535
+    t.integer "parent_id"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.integer "depth", default: 0, null: false
+    t.string "pathname", limit: 511, null: false
+    t.index ["id", "user_id"], name: "index_quantities_on_id_and_user_id", unique: true
+    t.index ["parent_id"], name: "index_quantities_on_parent_id"
+    t.index ["user_id", "parent_id", "name"], name: "index_quantities_on_user_id_and_parent_id_and_name", unique: true
+    t.index ["user_id"], name: "index_quantities_on_user_id"
+  end
+
+  create_table "readouts", force: :cascade do |t|
+    t.integer "user_id", null: false
+    t.integer "measurement_id"
+    t.integer "quantity_id", null: false
+    t.integer "category", default: 0, null: false
+    t.float "value", limit: 53, null: false
+    t.integer "unit_id", null: false
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["measurement_id", "quantity_id", "category"], name: "index_readouts_on_measurement_id_and_quantity_id_and_category", unique: true
+    t.index ["measurement_id"], name: "index_readouts_on_measurement_id"
+    t.index ["quantity_id"], name: "index_readouts_on_quantity_id"
+    t.index ["unit_id"], name: "index_readouts_on_unit_id"
+    t.index ["user_id"], name: "index_readouts_on_user_id"
+  end
+
+  create_table "units", force: :cascade do |t|
+    t.integer "user_id"
+    t.string "symbol", limit: 15, null: false
+    t.text "description", limit: 65535
+    t.float "multiplier", limit: 53, default: 1.0, null: false
+    t.integer "base_id"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["base_id"], name: "index_units_on_base_id"
+    t.index ["id", "user_id"], name: "index_units_on_id_and_user_id", unique: true
+    t.index ["user_id", "symbol"], name: "index_units_on_user_id_and_symbol", unique: true
+    t.index ["user_id"], name: "index_units_on_user_id"
+  end
+
+  create_table "users", force: :cascade do |t|
+    t.string "email", limit: 64, null: false
+    t.integer "status", default: 0, null: false
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.string "encrypted_password", default: "", null: false
+    t.string "reset_password_token"
+    t.datetime "reset_password_sent_at"
+    t.datetime "remember_created_at"
+    t.string "confirmation_token"
+    t.datetime "confirmed_at"
+    t.datetime "confirmation_sent_at"
+    t.string "unconfirmed_email", limit: 64
+    t.index ["confirmation_token"], name: "index_users_on_confirmation_token", unique: true
+    t.index ["email"], name: "index_users_on_email", unique: true
+    t.index ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
+  end
+
+  add_foreign_key "measurements", "notes", on_delete: :nullify
+  add_foreign_key "quantities", "quantities", column: "parent_id", on_delete: :cascade
+  add_foreign_key "quantities", "users", on_delete: :cascade
+  add_foreign_key "readouts", "measurements", on_delete: :cascade
+  add_foreign_key "readouts", "quantities", column: ["quantity_id", "user_id"], primary_key: ["id", "user_id"]
+  add_foreign_key "readouts", "quantities", on_delete: :cascade
+  add_foreign_key "readouts", "units", column: ["unit_id", "user_id"], primary_key: ["id", "user_id"]
+  add_foreign_key "readouts", "units", on_delete: :cascade
+  add_foreign_key "readouts", "users", on_delete: :cascade
+  add_foreign_key "units", "units", column: "base_id", on_delete: :cascade
+  add_foreign_key "units", "users", on_delete: :cascade
+end
--- a/lib/core_ext/active_model/validations/numericality_validates_precision_and_scale.rb
+++ b/lib/core_ext/active_model/validations/numericality_validates_precision_and_scale.rb
@@ -1,19 +0,0 @@
-module CoreExt::ActiveModel::Validations::NumericalityValidatesPrecisionAndScale
-  def validate_each(record, attr_name, value, ...)
-    super(record, attr_name, value, ...)
-
-    if options[:precision] || options[:scale]
-      attr_type = record.class.type_for_attribute(attr_name)
-      # For conversion of 'value' to BigDecimal 'ndigits' is not supplied intentionally,
-      # to avoid silent rounding. It is only required for conversion from Float and
-      # Rational, which should not happen.
-      value = BigDecimal(value) unless value.is_a? BigDecimal
-      if options[:precision] && (value.precision > attr_type.precision)
-        record.errors.add(attr_name, :precision_exceeded, **filtered_options(attr_type.precision))
-      end
-      if options[:scale] && (value.scale > attr_type.scale)
-        record.errors.add(attr_name, :scale_exceeded, **filtered_options(attr_type.scale))
-      end
-    end
-  end
-end
--- a/lib/core_ext/big_decimal_scientific_notation.rb
+++ b/lib/core_ext/big_decimal_scientific_notation.rb
@@ -1,36 +0,0 @@
-module CoreExt
-  module BigDecimalScientificNotation
-    def to_scientific
-      return 'NaN' unless finite?
-
-      sign, coefficient, base, exponent = split
-      (sign == -1 ? '-' : '') +
-        (coefficient.length > 1 ? coefficient.insert(1, '.') : coefficient) +
-        (exponent != 1 ? "e#{exponent-1}" : '')
-    end
-
-    # Converts value to HTML formatted scientific notation
-    def to_html
-      sign, coefficient, base, exponent = split
-      return 'NaN' unless sign
-
-      result = (sign == -1 ? '-' : '')
-      unless coefficient == '1' && sign == 1
-        if coefficient.length > 1
-          result += coefficient.insert(1, '.')
-        elsif
-          result += coefficient
-        end
-        if exponent != 1
-          result += "&times;"
-        end
-      end
-      if exponent != 1
-        result += "10<sup>% d</sup>" % [exponent-1]
-      end
-      result.html_safe
-    end
-  end
-end
-
-BigDecimal.prepend CoreExt::BigDecimalScientificNotation
--- a/lib/core_ext/float.rb
+++ b/lib/core_ext/float.rb
@@ -0,0 +1,54 @@
+# If a decimal string with at most 15 significant digits is converted to the
+# IEEE 754 double-precision format, giving a normal number, and then converted
+# back to a decimal string with the same number of digits, the final result
+# should match the original string.
+# If an IEEE 754 double-precision number is converted to a decimal string with
+# at least 17 significant digits, and then converted back to double-precision
+# representation, the final result must match the original number:
+#   ("%.16e" % self).to_f == self
+class Float
+  def to_scientific
+    sign, significand, exponent = split
+    sign + significand + (exponent != 0 ? "e#{exponent}" : '')
+  end
+
+  # Converts value to HTML formatted scientific notation.
+  def to_html(show_unity: true)
+    result, significand, exponent = split
+    result += significand if significand != '1' || (exponent == 0 && show_unity)
+    if exponent != 0
+      result += "&times;" if significand != '1'
+      result += "10<sup>% d</sup>" % exponent
+    end
+    result.html_safe
+  end
+
+  # Assume #finite? is true.
+  def limit(precision = DIG)
+    return 0.0 if precision.zero?
+    sign, significand, exponent = split(DIG_MAX)
+    "#{sign}#{significand[..precision]}e#{exponent}".to_f
+  end
+
+  private
+
+  SPLIT_FLOAT = /(-?)(.*?)\.?0*e(.*)/
+
+  # Format `%e` displays starting from significant digit (not 0).
+  def split(digits = DIG)
+    return ['', to_s[..2], 0] unless finite?
+    return ['', '0', 0] if digits.zero?
+    ("%.#{digits - 1}e" % self).match(SPLIT_FLOAT).captures
+      .then { |sign, significand, exponent| [sign, significand, exponent.to_i] }
+  end
+
+  # The maximum number of significant decimal digits in a double-precision
+  # floating point number.
+  DIG_MAX = 17
+  # Smallest and largest double-precision floating point numbers with DIG
+  # precision.
+  # TODO: change MIN_15 to MIN.ceil(MIN_10_EXP - DIG) after #ceil fix in Ruby
+  # v4.0.5: https://bugs.ruby-lang.org/issues/22079
+  MIN_15 = MIN.ceil(-(MIN_10_EXP - 1))
+  MAX_15 = MAX.floor(-(MAX_10_EXP - DIG + 1))
+end
--- a/lib/core_ext/range.rb
+++ b/lib/core_ext/range.rb
@@ -0,0 +1,31 @@
+class Range
+  # TODO: cleanup comments after commit
+  # * < nil, true < false
+  #if a.end == b.end
+  #  a.exclude_end? ^ b.exclude_end? ? (a.exclude_end? ? -1 : 1) : 0
+  #else
+  #  a.end <=> b.end || (a.end.nil? ? 1 : -1)
+  #end
+  #a.end == b.end ? (b.exclude_end? ? b : a) : [a, b].to_h.except(nil).min
+  #*(l[0] == r[0] ? (r[1] ? r : l) : [l, r].reject{ |e| e[0].nil? }.min)
+  def &(other)
+    case other
+    when Range
+      return nil unless self.overlap?(other)
+
+      both = [self, other]
+      return Range.new(
+        both.map(&:begin).compact.max,
+        *if self.end == other.end
+           other.exclude_end? ? [other] : [self]
+        else
+          both.select(&:end)
+        end.map { |r| [r.end, r.exclude_end?] }.min
+      )
+    when Array
+      return other.map { |o| self & o }.compact
+    else
+      return self.member?(other) ? other : nil
+    end
+  end
+end
--- a/lib/default_settings_strategy.rb
+++ b/lib/default_settings_strategy.rb
@@ -0,0 +1,55 @@
+class DefaultSettingsStrategy < ActiveRecord::Migration::DefaultStrategy
+  COLUMN_DEFAULTS = {
+    # TODO: all types `null: false` ?
+    # TODO: references `foreign_key: {on_delete: :cascade}` ?
+    # `timestamps` - Rails defaults to `null: false, precision: true`.
+    # `limit:` for `text` - `text` can be theoretically up to 1GB or
+    #   longer, so roughly unlimited for practical purposes. But:
+    #   * the actual usable length depends on additional factors, like compile
+    #     time limits (`SQLITE_MAX_LENGTH` in SQLite), runtime settings
+    #     (`max_allowed_packet` in MySQL) and probably other,
+    #   * Rails does not report limit for `text` column types, unless it is
+    #     explicitly set.
+    #   The decision is to always set safe limit and enforce it by validations, to
+    #   avoid surprises (e.g. text truncation) when saving to dabatase.
+    text: {limit: 2**16 - 1}
+  }
+  COLUMN_DEFAULTS.default = {}
+  COLUMN_DEFAULTS.freeze
+
+  module ColumnSettingsStrategy
+    def column(name, type, **options)
+      super(name, type, **COLUMN_DEFAULTS[type].merge(options))
+    end
+  end
+  ActiveRecord::ConnectionAdapters::TableDefinition.prepend ColumnSettingsStrategy
+
+  # `force: :cascade` - does nothing on MySQL, so `force:` is useless.
+  # `if_not_exists: true`/`if_exists: true` - without these options it's impossible
+  #   to change migration status once migration fails partially. If `up` migration
+  #   creates some, but not all objects, its status is not updated from `down` to
+  #   `up`. Then it's impossible to migrate: a) up - due to `already exists`
+  #   errors and b) down - due to migration status.
+  MIGRATION_DEFAULTS = {
+    add_check_constraint: {if_not_exists: true},
+    add_column:           {if_not_exists: true},
+    add_foreign_key:      {if_not_exists: true},
+    add_index:            {if_not_exists: true, unique: true},
+    add_timestamps:       {if_not_exists: true},
+    create_table:         {if_not_exists: true},
+    drop_table:               {if_exists: true},
+    remove_check_constraint:  {if_exists: true},
+    remove_column:            {if_exists: true},
+    remove_foreign_key:       {if_exists: true},
+    remove_index:             {if_exists: true},
+    remove_timestamps:        {if_exists: true},
+  }
+  MIGRATION_DEFAULTS.default = {}
+  MIGRATION_DEFAULTS.freeze
+
+  def method_missing(method, *args, **kwargs, &)
+    conflicts = kwargs.has_key?(:force) ? [:if_not_exists, :if_exists] : []
+    defaults = MIGRATION_DEFAULTS[method.to_sym].except(*conflicts)
+    super(method, *args, **defaults.merge(kwargs), &)
+  end
+end
--- a/lib/tasks/test_multi_db.rake
+++ b/lib/tasks/test_multi_db.rake
@@ -1,50 +0,0 @@
-namespace :test do
-  desc "Run Rails tests against all supported database adapters (SQLite, MySQL)"
-  task :all_adapters do
-    # DATABASE_URL overrides the adapter from database.yml at runtime.
-    # MySQL requires the mysql2 gem: bundle install --with mysql
-    adapters = {
-      "SQLite" => {
-        "DATABASE_URL" => "sqlite3:db/test.sqlite3"
-      },
-      "MySQL" => {
-        "DATABASE_URL" => format(
-          "mysql2://%s:%s@%s/%s",
-          ENV.fetch("DATABASE_USERNAME", "root"),
-          ENV.fetch("DATABASE_PASSWORD", ""),
-          ENV.fetch("DATABASE_HOST", "127.0.0.1"),
-          ENV.fetch("DATABASE_NAME", "fixin_test")
-        )
-      }
-    }
-
-    failed = []
-
-    adapters.each do |name, extra_env|
-      puts "\n#{"=" * 60}"
-      puts "  Running tests with #{name}"
-      puts "=" * 60
-
-      env = ENV.to_h.merge("RAILS_ENV" => "test").merge(extra_env)
-
-      # Reset test database; db:drop may fail on first run — that's fine
-      system(env, "bin/rails db:drop")
-      unless system(env, "bin/rails db:create db:schema:load")
-        failed << "#{name} (database setup)"
-        next
-      end
-
-      failed << name unless system(env, "bin/rails test")
-    end
-
-    puts "\n#{"=" * 60}"
-    if failed.any?
-      puts "  FAILED: #{failed.join(", ")}"
-      puts "=" * 60
-      exit 1
-    else
-      puts "  All adapters passed!"
-      puts "=" * 60
-    end
-  end
-end
--- a/public/icon.png
+++ b/public/icon.png
--- a/public/icon.svg
+++ b/public/icon.svg
@@ -0,0 +1,3 @@
+<svg width="512" height="512" xmlns="http://www.w3.org/2000/svg">
+  <circle cx="256" cy="256" r="256" fill="red"/>
+</svg>
--- a/test/application_system_test_case.rb
+++ b/test/application_system_test_case.rb
@@ -17,17 +17,20 @@ class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
    options.add_preference('browser.download.dir', "#{Rails.root}/tmp/")
  end

-  def sign_in(user: users.select(&:confirmed?).sample, password: randomize_user_password!(user))
+  def sign_in(user: users.select(&:confirmed?).sample,
+              password: randomize_user_password!(user))
    visit new_user_session_url
    fill_in User.human_attribute_name(:email), with: user.email
    fill_in User.human_attribute_name(:password), with: password
    click_on t(:sign_in)
+    yield if block_given?
    user
  end

-  def inject_button_to(after, *button_options)
+  def inject_button_to(inside, *button_options)
    button = button_to *button_options
-    evaluate_script("arguments[0].insertAdjacentHTML('beforeend', '#{button.html_safe}');", after)
+    inside.evaluate_script("this.insertAdjacentHTML('beforeend', arguments[0]);",
+                           button.html_safe)
  end

  # Allow skipping interpolations when translating for testing purposes
@@ -38,6 +41,32 @@ class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
  end
  alias :t :translate

+  DB_CONFIGS = ActiveRecord::Base.configurations.configs_for(env_name: "test")
+  TEST_CONFIGS = Hash.new(DB_CONFIGS.first.name.to_sym)
+  class << self
+    # NOTE: alternative to current solution is to create shards:
+    #   ActiveRecord::Base.connects_to(
+    #     shards: {mysql2: {writing: :mysql2}, sqlite3: {writing: :sqlite3}}
+    #   )
+    # and use them in one of the following ways:
+    # * set config.active_record.shard_selector/shard_resolver
+    # * run tests within: ActiveRecord::Base.connected_to(shard: :sqlite3) { test_ }
+    # Remove this note once current solution is confirmed to work.
+    #
+    # Test block should not be modified here, as it would change its binding from
+    # instance level to class level.
+    if DB_CONFIGS.many?
+      def test(name, ...)
+        DB_CONFIGS.each do |config|
+          TEST_CONFIGS[super("#{config.name} #{name}", ...)] = config.name.to_sym
+        end
+      end
+    end
+  end
+  setup do
+    ActiveRecord::Base.establish_connection(TEST_CONFIGS[name.to_sym])
+  end
+
  #def assert_stale(element)
  #  assert_raises(Selenium::WebDriver::Error::StaleElementReferenceError) { element.tag_name }
  #end
--- a/test/controllers/default/units_controller_test.rb
+++ b/test/controllers/default/units_controller_test.rb
@@ -1,12 +1,8 @@
 require "test_helper"

 class Default::UnitsControllerTest < ActionDispatch::IntegrationTest
-  setup do
-    sign_in users(:alice)
-  end
-
  test "should get index" do
-    get default_units_url
+    get units_defaults_index_url
    assert_response :success
  end
 end
--- a/test/controllers/measurements_controller_test.rb
+++ b/test/controllers/measurements_controller_test.rb
@@ -1,8 +0,0 @@
-require "test_helper"
-
-class MeasurementsControllerTest < ActionDispatch::IntegrationTest
-  #test "should get index" do
-  #  get measurements_index_url
-  #  assert_response :success
-  #end
-end
--- a/test/controllers/quantities_controller_test.rb
+++ b/test/controllers/quantities_controller_test.rb
@@ -1,7 +0,0 @@
-require "test_helper"
-
-class QuantitiesControllerTest < ActionDispatch::IntegrationTest
-  # test "the truth" do
-  #   assert true
-  # end
-end
--- a/test/controllers/units_controller_test.rb
+++ b/test/controllers/units_controller_test.rb
@@ -1,7 +0,0 @@
-require "test_helper"
-
-class UnitsControllerTest < ActionDispatch::IntegrationTest
-  # test "the truth" do
-  #   assert true
-  # end
-end
--- a/test/controllers/users_controller_test.rb
+++ b/test/controllers/users_controller_test.rb
@@ -1,10 +1,10 @@
 require "test_helper"

+# TODO: make sure tested actions are covered by system tests and remove all
+# controller tests.
 class UsersControllerTest < ActionDispatch::IntegrationTest
  setup do
-    @admin = users(:admin)
-    @user = users(:alice)
-    sign_in @admin
+    @user = users(:one)
  end

  test "should get index" do
@@ -12,25 +12,39 @@ class UsersControllerTest < ActionDispatch::IntegrationTest
    assert_response :success
  end

+  test "should get new" do
+    get new_user_url
+    assert_response :success
+  end
+
+  test "should create user" do
+    assert_difference("User.count") do
+      post users_url, params: { user: { email: @user.email, status: @user.status } }
+    end
+
+    assert_redirected_to user_url(User.last)
+  end
+
  test "should show user" do
    get user_url(@user)
    assert_response :success
  end

+  test "should get edit" do
+    get edit_user_url(@user)
+    assert_response :success
+  end
+
  test "should update user" do
-    patch user_url(@user), params: { user: { status: :restricted } }, as: :turbo_stream
-    assert_equal "restricted", @user.reload.status
+    patch user_url(@user), params: { user: { email: @user.email, status: @user.status } }
+    assert_redirected_to user_url(@user)
  end

-  test "should not update self" do
-    patch user_url(@admin), params: { user: { status: :active } }, as: :turbo_stream,
-      headers: { "HTTP_REFERER" => users_url }
-    assert_response :redirect
-  end
+  test "should destroy user" do
+    assert_difference("User.count", -1) do
+      delete user_url(@user)
+    end

-  test "should forbid non-admin" do
-    sign_in @user
-    get users_url
-    assert_response :forbidden
+    assert_redirected_to users_url
  end
 end
--- a/test/models/user_test.rb
+++ b/test/models/user_test.rb
@@ -1,7 +0,0 @@
-require "test_helper"
-
-class UserTest < ActiveSupport::TestCase
-  # test "the truth" do
-  #   assert true
-  # end
-end
--- a/test/system/tasks_test.rb
+++ b/test/system/tasks_test.rb
@@ -0,0 +1,20 @@
+require 'application_system_test_case'
+
+Rails.application.load_tasks
+# NOTE: for some reason task for checking pending migrations messes up
+# transaction when run during test. It causes all DB changes made before its
+# execution to be rolled back.
+# Run it before tests, so any rake task dependent on it will see it as
+# #already_invoked and won't run it during test. It is redundant anyway, as
+# migrations are run before starting test suite.
+Rake::Task['db:abort_if_pending_migrations'].invoke
+
+class TasksTest < ApplicationSystemTestCase
+  test "db:seed creates admin account" do
+    User.admin.delete_all
+    assert_output /Creating admin account/ do
+      Rake::Task['db:seed'].execute
+    end
+    assert User.admin.exists?
+  end
+end
--- a/test/system/units_test.rb
+++ b/test/system/units_test.rb
@@ -1,33 +1,36 @@
 require "application_system_test_case"

 # Fixture prerequisites:
-#  * user with multiple units + subunits
-#  * user with single unit
-#  * user with no units
+#  * user with multiple units (at least 1 w/o subunit) + subunits,
+#  * user with single unit,
+# FIXME: add confirmed user without units
+#  * user with no units.
+# Users need to be active and confirmed.

 class UnitsTest < ApplicationSystemTestCase
-  LINK_LABELS = {}
+  def sign_in(...)
+    @link_labels = nil
+    @user = super { click_on t('units.navigation') }
+  end

-  setup do
-    @user = sign_in
-
-    LINK_LABELS.clear
-    LINK_LABELS[:new_unit] = t('units.index.new_unit')
-    LINK_LABELS[:new_subunit] = t('units.unit.new_subunit')
-    LINK_LABELS[:edit] = Regexp.union(@user.units.map(&:symbol))
-
-    visit units_path
+  def link_labels
+    @link_labels ||= {
+      new_unit:     t('units.index.new_unit'),
+      new_subunit:  t('units.unit.new_subunit'),
+      edit:         Regexp.union(@user.units.map(&:symbol))
+    }
  end

  test "index" do
-    # Wait for the table to appear first, only then check row count
+    sign_in
+    # Wait for the table to appear first, only then check row count.
    within 'tbody' do
      assert_selector 'tr', count: @user.units.count
    end

-    # Cannot #destroy_all due to {dependent: :restrict*} on Unit.subunits association
+    # Cannot #destroy_all due to {dependent: :restrict*} on Unit.subunits association.
    @user.units.delete_all
-    visit units_path
+    refresh
    within 'tbody' do
      assert_selector 'tr', count: 1
      assert_text t('units.no_items')
@@ -35,7 +38,9 @@ class UnitsTest < ApplicationSystemTestCase
  end

  test "new and create" do
-    type, label = LINK_LABELS.assoc([:new_unit, :new_subunit].sample)
+    sign_in
+    link_labels.slice!(:new_unit, :new_subunit)
+    type, label = link_labels.to_a.sample
    new_link = all(:link, exact_text: label).sample
    new_link.click
    assert_equal 'disabled', new_link[:disabled]
@@ -44,10 +49,12 @@ class UnitsTest < ApplicationSystemTestCase
    within 'tbody > tr:has(input[type=text], textarea)' do
      assert_selector ':focus'

-      maxlength = all(:fillable_field).to_h { |f| [f[:name], f[:maxlength].to_i || 2**16] }
+      maxlength = all(:fillable_field).to_h do |field|
+        [field[:name], field[:maxlength].to_i || 2**16]
+      end
      values = {
-        symbol: random_string(rand([1..3, 4..maxlength['unit[symbol]']].sample),
-                              except: units.map(&:symbol)),
+        symbol: random_string(deep_rand(1..3, 4..maxlength['unit[symbol]']),
+                              except: @user.units.map(&:symbol), allow_blank: false),
        description: random_string(rand(0..maxlength['unit[description]']))
      }.with_indifferent_access
      within :field, 'unit[multiplier]' do |field|
@@ -61,34 +68,60 @@ class UnitsTest < ApplicationSystemTestCase
      end
    end

-    assert_selector '.flash.notice', text: t('units.create.success', unit: Unit.last.symbol)
+    assert_selector '.flash.notice',
+      text: t('units.create.success', unit: Unit.last.symbol)
    within 'tbody' do
      assert_no_selector :fillable_field
      assert_selector 'tr', count: @user.units.count
    end
    assert_no_selector :element, :a, 'disabled': 'disabled',
-      exact_text: Regexp.union(LINK_LABELS.fetch_values(:new_unit, :new_subunit))
+      exact_text: Regexp.union(link_labels.values)
    assert_equal values, Unit.last.attributes.slice(*values.keys)
  end

+  test "create updates view in order" do
+    # Destroy and re-create unit to verify its index position is unchanged.
+    sign_in(user: users.select { |u| u.confirmed? && u.units.many? }.sample)
+
+    link = all(:link_or_button, exact_text: t('units.unit.destroy')).sample
+    symbol = link.ancestor('tr').first(:link).text
+    index = link.ancestor('tbody').all('tr').index { |e| e.first(:link).text == symbol }
+    unit = @user.units.find_by(symbol: symbol)
+
+    link.click
+    if unit.base_id?
+      find_link(unit.base.symbol).ancestor('tr').click_on(t('units.unit.new_subunit'))
+      fill_in 'unit[multiplier]', with: unit.multiplier
+    else
+      click_on t('units.index.new_unit')
+    end
+    fill_in 'unit[symbol]', with: unit.symbol
+    click_on t('helpers.submit.create')
+
+    within "tbody > tr:nth-child(#{index+1})" do
+      assert_selector :link, exact_text: symbol
+    end
+  end
+
  test "new and edit on validation error" do
-    # It's not possible to cause validation error on :edit with single unit
-    LINK_LABELS.delete(:edit) unless @user.units.count > 1
-    type, label = LINK_LABELS.to_a.sample
+    sign_in
+    # It's impossible to cause validation error on :edit with single unit.
+    link_labels.delete(:edit) unless @user.units.many?
+    type, label = link_labels.to_a.sample
    link = all(:link, exact_text: label).sample
    link.click

    get_values = -> { all(:field).map { |f| [f[:name], f[:value]] }.to_h }
    values = nil
    within 'tbody > tr:has(input[type=text])' do
-      # Provide duplicate :symbol as input invalidatable server side
+      # Provide duplicate :symbol as input invalidatable server side.
      fill_in 'unit[symbol]',
        with: (@user.units.map(&:symbol) - [find_field('unit[symbol]').value]).sample
      values = get_values[]
      send_keys :enter
    end

-    # Wait for flash before checking link :disabled status
+    # Wait for flash before checking link :disabled status.
    assert_selector '.flash.alert'
    if type == :edit
      assert_no_selector :link, exact_text: link[:text]
@@ -102,15 +135,18 @@ class UnitsTest < ApplicationSystemTestCase
  end

  test "new and edit allow opening multiple forms" do
-    # Requires at least 1 unit to be able to open 2 forms
-    links = LINK_LABELS.transform_values { |labels| all(:link, exact_text: labels).to_a }
+    # Require at least 1 unit to be able to open 2 forms.
+    sign_in(user: users.select { |u| u.confirmed? && u.units.any? }.sample)
+    links = link_labels.transform_values do |labels|
+      all(:link, exact_text: labels).to_a
+    end
    random_link = ->{ links.transform_values(&:sample).compact.to_a.sample }
-    # Define tr count change depending on link clicked
+    # Define <tr> count change depending on link clicked.
    tr_diff = {new_unit: 1, new_subunit: 1, edit: 0}

    type, link = random_link[].tap { |t, l| links[t].delete(l) }
    subunit_link = link.ancestor('tr')
-      .first(:link, LINK_LABELS[:new_subunit], between: 0..1) if type == :edit
+      .first(:link, link_labels[:new_subunit], between: 0..1) if type == :edit
    assert_difference ->{ all('tbody tr').count }, tr_diff[type] do
      assert_difference ->{ all('tbody tr:has(input[type=text])').count }, 1 do
        link.click
@@ -135,12 +171,14 @@ class UnitsTest < ApplicationSystemTestCase
    assert_not_equal form, find('tbody tr:has(input:focus)')
  end

-  #test "edit" do
+  test "edit" do
    # NOTE: Check if displayed attributes match record
-  #end
+    assert true
+  end

  # NOTE: extend with any add/edit link
-  test "close new unit form with escape key" do
+  test "new form closes on escape key" do
+    sign_in
    click_on t('units.index.new_unit')
    first('tbody > tr').all(:field).sample.send_keys :escape
    within 'tbody' do
@@ -149,7 +187,8 @@ class UnitsTest < ApplicationSystemTestCase
  end

  # NOTE: extend with any add/edit link
-  test "close and reopen new unit form" do
+  test "new form can be reopened after close" do
+    sign_in
    click_on t('units.index.new_unit')
    within 'tbody' do
      find(:link_or_button, exact_text: t(:cancel)).click
@@ -159,13 +198,19 @@ class UnitsTest < ApplicationSystemTestCase
    assert_selector 'tbody > tr:has(input, textarea)'
  end

+  test "rebase" do
+    # TODO
+    assert true
+  end
+
  test "destroy" do
+    sign_in(user: users.select { |u| u.confirmed? && u.units.any? }.sample)
    link = all(:link_or_button, exact_text: t('units.unit.destroy')).sample
-    label = link.ancestor('tr').first(:link)[:text]
+    symbol = link.ancestor('tr').first(:link).text
    assert_difference ->{ @user.units.count }, -1 do
      link.click
    end
    assert_selector 'tbody tr', count: [@user.units.count, 1].max
-    assert_selector '.flash.notice', text: t('units.destroy.success', unit: label)
+    assert_selector '.flash.notice', text: t('units.destroy.success', unit: symbol)
  end
 end
--- a/test/system/users_test.rb
+++ b/test/system/users_test.rb
@@ -1,5 +1,6 @@
 require "application_system_test_case"

+# TODO: review #visit usage and replace with #click_on where applicable
 class UsersTest < ApplicationSystemTestCase
  setup do
    @admin = users(:admin)
@@ -204,6 +205,7 @@ class UsersTest < ApplicationSystemTestCase

  test 'update profile' do
    # TODO
+    assert true
  end

  test 'update status' do
@@ -227,7 +229,8 @@ class UsersTest < ApplicationSystemTestCase

    within all(:xpath, "//tbody//tr[not(descendant::select)]").sample do |tr|
      user = User.find_by_email!(first(:link).text)
-      inject_button_to first('td:not(.link)'), "update status", user_path(user), method: :patch,
+      inject_button_to find('td', exact_text: user.status), "update status",
+        user_path(user), method: :patch,
        params: {user: {status: User.statuses.keys.sample}}, data: {turbo: false}
      click_on "update status"
    end
@@ -237,8 +240,8 @@ class UsersTest < ApplicationSystemTestCase
  test 'update status forbidden for non admin' do
    sign_in user: users.reject(&:admin?).select(&:confirmed?).sample
    visit units_path
-    inject_button_to find('body'), "update status", user_path(User.all.sample), method: :patch,
-      params: {user: {status: User.statuses.keys.sample}}
+    inject_button_to find('body'), "update status", user_path(User.all.sample),
+      method: :patch, params: {user: {status: User.statuses.keys.sample}}
    click_on "update status"
    assert_text t('actioncontroller.exceptions.status.forbidden')
  end
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -2,14 +2,7 @@ ENV["RAILS_ENV"] ||= "test"
 require_relative "../config/environment"
 require "rails/test_help"

-class ActionDispatch::IntegrationTest
-  include Devise::Test::IntegrationHelpers
-end
-
 class ActiveSupport::TestCase
-  # Run tests in parallel with specified workers
-  parallelize(workers: :number_of_processors)
-
  # Setup all fixtures in test/fixtures/*.yml for all tests in alphabetical order.
  fixtures :all

@@ -17,27 +10,100 @@ class ActiveSupport::TestCase
  include ActionView::Helpers::TranslationHelper

  # List of categorized Unicode characters:
-  # * http://www.unicode.org/Public/UNIDATA/UnicodeData.txt
-  # File format: http://www.unicode.org/L2/L1999/UnicodeData.html
-  # Select from graphic ranges: L, M, N, P, S, Zs
-  UNICODE_CHARS = {
-    1 => [*"\u0020".."\u007E"],
-    2 => [*"\u00A0".."\u00AC",
-          *"\u00AE".."\u05FF",
-          *"\u0606".."\u061B",
-          *"\u061D".."\u06DC",
-          *"\u06DE".."\u070E",
-          *"\u0710".."\u07FF"]
-  }
-  UNICODE_CHARS.default = UNICODE_CHARS[1] + UNICODE_CHARS[2]
-  def random_string(bytes = 10, except: [])
+  #   * source: http://www.unicode.org/Public/UNIDATA/UnicodeData.txt
+  #   * file format: http://www.unicode.org/L2/L1999/UnicodeData.html
+  #   * select from graphic ranges: L, M, N, P, S, Zs
+  UNICODE_CHARS = [
+    *"\u0020".."\u007E",
+    *"\u00A0".."\u00AC",
+    *"\u00AE".."\u05FF",
+    *"\u0606".."\u061B",
+    *"\u061D".."\u06DC",
+    *"\u06DE".."\u070E",
+    *"\u0710".."\u07FF"
+  ]
+  def random_string(length, except: [], allow_blank: true)
+    # Rails String#blank? is based on [[:space:]] character class (String::BLANK_RE).
+    # Here we use more general class including tabs, cariage returns and newlines.
+    except << /^\p{Space}+$/ unless allow_blank
    begin
-      result = ''
-      result += UNICODE_CHARS[bytes - result.bytesize].sample while bytes > result.bytesize
-    end while except.include?(result)
+      result = UNICODE_CHARS.sample(length).join
+    end while except.any? { |e| e === result }
    result
  end

+  # Range based string generation. Not finished, but saved as a potential
+  # reference for future work. To work properly it needs to sort in collation
+  # order of database.
+  #def random_between(from, to, maxlength)
+  #  # TODO: sort UNICODE_CHARS
+  #  byebug
+  #  result = ''
+  #  maxlength.times do |i|
+  #    case
+  #    when from[i] == to[i]
+  #      result += from[i]
+  #    else
+  #      from_index = UNICODE_CHARS.bsearch_index(from[i] || UNICODE_CHARS[0])
+  #      to_index = UNICODE_CHARS.bsearch_index(to[i])
+  #      index = rand(from_index..to_index)
+  #      case
+  #      when index == from_index
+  #        result += UNICODE_CHARS[index]
+  #        from[i+1..].each_char do |c|
+  #          from_index = UNICODE_CHARS.bsearch_index(from[i])
+  #          index = rand(from_index..UNICODE_CHARS.length-1)
+  #          result += UNICODE_CHARS[index]
+  #          break if index != from_index
+  #        end
+  #        if result == from
+  #          if result.length < maxlength
+  #            result += UNICODE_CHARS.sample
+  #          else
+  #            # TODO: succ result[i..]
+  #            # raise if result == to
+  #          end
+  #        end
+  #        break
+  #      when index == to_index
+  #        result += UNICODE_CHARS[index]
+  #        to[i+1..].each_char do |c|
+  #          to_index = UNICODE_CHARS.bsearch_index(to[i])
+  #          index = rand(-1..to_index)
+  #          break if index == -1
+  #          result += UNICODE_CHARS[index]
+  #          break if index != to_index
+  #        end
+  #        if result == to
+  #          if result.length > i+1
+  #            result = result[..-2]
+  #          else
+  #            # TODO: prev result[i..]
+  #            # raise if result == from
+  #          end
+  #        end
+  #        break
+  #      else
+  #        result += UNICODE_CHARS[index]
+  #        break
+  #      end
+  #    end
+  #  end
+  #  return result += UNICODE_CHARS.sample(rand(0..maxlength-i-1)).join
+  #  # if result == from/to ...
+  #end
+
+  def deep_rand(*args)
+    case args
+    when Array
+      args = args.sample
+    when Range
+      args = rand(args)
+    else
+      return args
+    end while true
+  end
+
  # Assumes: max >= step and step = 1e[-]N, both as strings
  def random_number(max, step)
    max.delete!('.')
Author	SHA1	Message	Date
cryptogopher	0e0cfeff10	Change Unit.multiplier type from decimal to float Remove remnants related to BigDecimal.	2026-05-23 17:02:01 +02:00
cryptogopher	1ab925f6fa	Improve Units tests and remove test parallelization Parallelization produces errors (#92)	2026-05-15 00:21:10 +02:00
cryptogopher	83168092f1	Fix SQLite query compatibility inside WITH clause SQLite3::SQLException: circular reference	2026-05-15 00:21:01 +02:00
cryptogopher	852e6e7cea	Fix test passing blank input into required field	2026-05-15 00:20:28 +02:00
cryptogopher	0481b0f6f1	Allow Capybara test server IP in HostAuthorization	2026-05-07 20:53:18 +02:00
cryptogopher	76b95f7c30	Set default `:text` type column limit	2026-05-07 18:20:06 +02:00
cryptogopher	ca7edb99e1	Add Note	2026-05-07 18:17:30 +02:00
cryptogopher	98044fc04a	Remove empty test files	2026-05-05 23:41:08 +02:00
cryptogopher	d3a34233b9	Set constraints on Readouts.user_id foreign key Add Measurements table	2026-05-05 20:36:57 +02:00
cryptogopher	4a36ffc8bf	Move migration defaults to ActiveRecord migration strategy Remove redundant defaults	2026-05-05 20:36:51 +02:00
cryptogopher	78639b4c1e	Upgrade Rails to 8.1.3	2026-05-05 20:35:00 +02:00
cryptogopher	c4def9cd86	Filter :email field logging only in production env	2026-04-30 18:26:43 +02:00
cryptogopher	3454d3052b	Generate admin password on db:seed Test admin account creation in db:seed	2026-04-30 18:23:00 +02:00
cryptogopher	dedea0246f	Run tests on multiple database configurations	2026-04-27 17:38:49 +02:00
cryptogopher	3ac3a6f13c	Drop Readout.value decimal type in favor of float	2026-04-25 18:20:16 +02:00
cryptogopher	97e7bfedf7	Upgrade Rails to 8.0.5 Install sqlite3 Migrate Rails default settings from 7.2 to 8.0	2026-04-25 04:13:47 +02:00
cryptogopher	a05767213c	Fix test based on unavailable `td.link` selector	2026-04-25 04:13:47 +02:00
cryptogopher	d002ae0f2c	Clean up and improve items-table styling Closes #9	2026-04-25 04:13:47 +02:00
cryptogopher	f87aa9fd3d	Improve Measurement form layout and styling	2026-04-25 04:13:47 +02:00
cryptogopher	5ed066ad18	Unify border/outline parameters order	2026-03-06 01:42:32 +01:00
cryptogopher	dde4e52f1b	Fix form elements styling on hover	2026-03-06 01:33:23 +01:00
cryptogopher	a9091d76a8	Merge styles of <a>.button/<button>/<input type="submit"> into .button Remove flash button Fix some multi-selector specificity differences	2026-03-04 17:13:11 +01:00
cryptogopher	4175d31b9d	Update and format comments	2026-03-03 01:31:44 +01:00
cryptogopher	c659201904	Make [disabled] and [hidden] styles !important	2026-03-03 01:14:12 +01:00