Extend all test tasks to run against every configured test database

When database.yml defines more than one top-level key starting with "test",
every standard test task (rails test, rails test:models, rails test:system,
rails test:controllers, …) is automatically rewritten at load time to run
the full suite against each configured database in turn.

Single-database setups are completely unaffected — the wrapping code
activates only when test_configs.size > 1, so existing behaviour is
preserved by default.

Convention: test: is the required primary; test_<name>: adds an adapter:
  test_sqlite:
    adapter: sqlite3
    database: db/fixinme_test.sqlite3
  test_pg:
    adapter: postgresql
    ...

Mechanism:
- lib/tasks/test_databases.rake loads after railties/testing.rake (which
  defines all test tasks). For each task in the wrapped set it calls
  Rake::Task[name].clear_actions and re-enhances with a block that loops
  over DB configs, writing a temporary database.yml per database and
  running "rails <task_name>" as a subprocess with RAILS_DATABASE_YML set.
- config/application.rb(.dist): reads RAILS_DATABASE_YML and overrides
  Rails' database config path before initialisation — no monkey-patching
  of the test runner required.
- Adapter gem availability is checked before each run; missing adapters are
  skipped with a hint on which bundle group to enable.
- A formatted summary (✓/✗ per database) is printed; exits non-zero on
  any failure.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

DESIGN.md

@@ -0,0 +1,34 @@
+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,
+        * 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 all 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

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>

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>

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 +141,108 @@ 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;
+}
+[name=cancel],
+.auxiliary {
+  border-color: var(--color-border-gray);
+  color: var(--color-nav-gray);
+  fill: var(--color-nav-gray);
+}
+.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 +252,24 @@ 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;
+.link:hover {
+  color: var(--color-blue);
+  text-decoration-color: var(--color-blue);
 }
-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;
+table .button {
+  border-color: var(--color-border-gray);
+  color: var(--color-table-gray);
+  font-weight: normal;
+  height: 100%;
+  padding: 0.4em;
 }
 
 
-/* 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 +277,16 @@ 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 +302,14 @@ 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 +341,7 @@ 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 +357,42 @@ 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();
   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 {
   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 +409,7 @@ 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 +429,117 @@ 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;
 }
 
+.tabular-form table {
+  border: none;
+  border-spacing: 0.4em 0;
+  margin-inline: -0.4em;
+}
+.tabular-form table td {
+  border: none;
+  vertical-align: middle;
+}
+.tabular-form table td {
+  padding-inline: 0;
+}
+.tabular-form table :is(form, input, select, textarea):only-child {
+  margin-inline-start: 0;
+}
 
-/* TODO: remove .items class (?) and make 'form table' work properly */
-table.items {
+
+.items-table {
   border-spacing: 0;
-  border: solid 1px var(--color-border-gray);
+  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 +547,18 @@ 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 +570,12 @@ 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 +587,7 @@ 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 +598,15 @@ 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 +628,15 @@ 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;
+}

app/controllers/measurements_controller.rb

@@ -1,13 +1,7 @@
 class MeasurementsController < ApplicationController
-  before_action except: :index do
-    raise AccessForbidden unless current_user.at_least(:active)
-  end
-
   def index
-    readouts = current_user.readouts.includes(:quantity, :unit).order(created_at: :desc)
-    @measurements = readouts.group_by(&:created_at).map do |created_at, grouped|
-      Measurement.new(created_at: created_at, readouts: grouped)
-    end
+    @measurements = []
+    #@measurements = current_user.units.ordered.includes(:base, :subunits)
   end
 
   def new
@@ -15,33 +9,8 @@ class MeasurementsController < ApplicationController
   end
 
   def create
-    timestamp = Time.current
-    @readouts = readout_params.map do |rp|
-      r = current_user.readouts.new(rp)
-      r.created_at = timestamp
-      r
-    end
-
-    if @readouts.all?(&:valid?)
-      Readout.transaction { @readouts.each(&:save!) }
-      @measurement = Measurement.new(readouts: @readouts, created_at: timestamp)
-      flash.now[:notice] = t('.success')
-    else
-      render :new, status: :unprocessable_entity
-    end
   end
 
   def destroy
-    @measurement = Measurement.new(id: params[:id].to_i,
-                                   created_at: Time.at(params[:id].to_i))
-    current_user.readouts.where(created_at: @measurement.created_at).delete_all
-    @measurements_empty = current_user.readouts.empty?
-    flash.now[:notice] = t('.success')
-  end
-
-  private
-
-  def readout_params
-    params.require(:readouts).map { |r| r.permit(:quantity_id, :value, :unit_id) }
   end
 end

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 +102,28 @@ module ApplicationHelper
 
     def number_field(method, options = {})
       attr_type = object.type_for_attribute(method)
-      if attr_type.type == :decimal
+      case attr_type.type
+      when :decimal
         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[:size] ||= attr_type.precision / 2
+      when :float
+        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 +152,14 @@ 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)
@@ -212,9 +228,8 @@ 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("×"), 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

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

app/models/measurement.rb

@@ -1,17 +1,3 @@
 class Measurement
   include ActiveModel::Model
-
-  attr_accessor :readouts, :created_at
-
-  def id
-    created_at.to_i
-  end
-
-  def to_param
-    id.to_s
-  end
-
-  def persisted?
-    true
-  end
 end

app/models/quantity.rb

@@ -15,8 +15,8 @@ class Quantity < ApplicationRecord
     errors.add(:parent, :descendant_reference) if ancestor_of?(parent)
   end
   validates :name, presence: true, uniqueness: {scope: [:user_id, :parent_id]},
-    length: {maximum: type_for_attribute(:name).limit || Float::INFINITY}
-  validates :description, length: {maximum: type_for_attribute(:description).limit || Float::INFINITY}
+    length: {maximum: type_for_attribute(:name).limit}
+  validates :description, length: {maximum: type_for_attribute(:description).limit}
 
   # Update :depths of progenies after parent change
   before_save if: :parent_changed? do
@@ -61,26 +61,18 @@ class Quantity < ApplicationRecord
 
   # Return: ordered [sub]hierarchy
   scope :ordered, ->(root: nil, include_root: true) {
-    if connection.adapter_name =~ /mysql/i
-      numbered = Arel::Table.new('numbered')
-      self.model.with(numbered: numbered(:parent_id, :name)).with_recursive(arel_table.name => [
-        numbered.project(
-          numbered[Arel.star],
-          numbered.cast(numbered[:child_number], 'BINARY').as('path')
-        ).where(numbered[root && include_root ? :id : :parent_id].eq(root)),
-        numbered.project(
-          numbered[Arel.star],
-          arel_table[:path].concat(numbered[:child_number])
-        ).join(arel_table).on(numbered[:parent_id].eq(arel_table[:id]))
-      ]).order(arel_table[:path])
-    elsif root.nil?
-      # SQLite: pathname column already stores the full hierarchical path
-      order(:pathname)
-    else
-      root_pathname = unscoped.where(id: root).pick(:pathname)
-      scope = order(:pathname).where("pathname LIKE ?", "#{root_pathname}#{PATHNAME_DELIMITER}%")
-      include_root ? scope.or(where(id: root)) : scope
-    end
+    numbered = Arel::Table.new('numbered')
+
+    self.model.with(numbered: numbered(:parent_id, :name)).with_recursive(arel_table.name => [
+      numbered.project(
+        numbered[Arel.star],
+        numbered.cast(numbered[:child_number], 'BINARY').as('path')
+      ).where(numbered[root && include_root ? :id : :parent_id].eq(root)),
+      numbered.project(
+        numbered[Arel.star],
+        arel_table[:path].concat(numbered[:child_number])
+      ).join(arel_table).on(numbered[:parent_id].eq(arel_table[:id]))
+    ]).order(arel_table[:path])
   }
 
   # TODO: extract named functions to custom Arel extension

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',

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>

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) %>

app/views/measurements/_form.html.erb

@@ -1,28 +1,37 @@
 <%= 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') %>
   </div>

app/views/measurements/_measurement.html.erb

@@ -1,14 +0,0 @@
-<%= tag.tr id: dom_id(measurement) do %>
-  <td><%= l measurement.created_at, format: :short %></td>
-  <td>
-    <% measurement.readouts.each do |readout| %>
-      <span><%= readout.quantity.name %>: <%= readout.value %> <%= readout.unit %></span>
-    <% end %>
-  </td>
-  <% if current_user.at_least(:active) %>
-    <td class="actions">
-      <%= image_button_to t('.destroy'), 'delete-outline', measurement_path(measurement),
-        method: :delete %>
-    </td>
-  <% end %>
-<% end %>

app/views/measurements/create.turbo_stream.erb

@@ -1,5 +0,0 @@
-<%= turbo_stream.update :flashes %>
-<%= turbo_stream.remove :measurement_form %>
-<%= turbo_stream.remove :no_items %>
-<%= turbo_stream.enable :new_measurement_link %>
-<%= turbo_stream.prepend :measurements, @measurement %>

app/views/measurements/destroy.turbo_stream.erb

@@ -1,3 +0,0 @@
-<%= turbo_stream.update :flashes %>
-<%= turbo_stream.remove @measurement %>
-<%= turbo_stream.append(:measurements, render_no_items) if @measurements_empty %>

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}) %>

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} %>
 

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>

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 %>

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">
+    <td>
       <%= form.number_field :multiplier, required: true, size: 10, min: :step 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}) %>

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 %></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} %>

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>

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 %>

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)} %>

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 %>

config/application.rb.dist

@@ -20,6 +20,10 @@ Bundler.require(*Rails.groups)
 
 module FixinMe
   class Application < Rails::Application
+    # Allow RAILS_DATABASE_YML to override the database config file path.
+    # Used by the multi-database test runner (lib/tasks/test_databases.rake).
+    config.paths['config/database'] = [ENV['RAILS_DATABASE_YML']] if ENV['RAILS_DATABASE_YML']
+
     # Initialize configuration defaults for originally generated Rails version.
     config.load_defaults 7.0
 

config/database.yml.dist

@@ -48,3 +48,24 @@ production:
 #test:
 #  <<: *default
 #  database: fixinme_test
+
+# Multi-database testing
+# ----------------------
+# Any key starting with "test" is treated as a test database.
+# When more than one is present, EVERY test task (rails test, rails test:models,
+# rails test:system, …) automatically runs against all of them.
+#
+# The adapter gem must be available:
+#   bundle config --local with "mysql sqlite"   # mysql + sqlite
+#   bundle config --local with "mysql pg"       # mysql + postgresql
+#
+#test_sqlite:
+#  adapter: sqlite3
+#  database: db/fixinme_test.sqlite3
+#
+#test_pg:
+#  adapter: postgresql
+#  database: fixinme_test
+#  username: fixinme
+#  password: Some-password1%
+#  host: localhost

config/locales/en.yml

@@ -85,18 +85,10 @@ 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 
     index:
       new_measurement: Add measurement
-    create:
-      success: Measurement saved.
-    destroy:
-      success: Measurement deleted.
-    measurement:
-      destroy: Delete
-  readouts:
-    form:
-      select_unit: ...
   quantities:
     navigation: Quantities
     no_items: There are no configured quantities. You can Add some or Import from defaults.

db/migrate/20250121230456_create_readouts.rb

@@ -1,10 +1,14 @@
 class CreateReadouts < ActiveRecord::Migration[7.2]
   def change
     create_table :readouts do |t|
-      t.references :user, null: false, foreign_key: true
+      # Reference :user through :quantity (:measurement may be NULL).
+      t.references :measurement, foreign_key: true
       t.references :quantity, null: false, foreign_key: true
+      # :category + :value + :unit as a separate table? (NumericValue, TextValue)
+      t.integer :category, null: false, default: 0
+      t.float :value, null: false, limit: Float::MANT_DIG
       t.references :unit, foreign_key: true
-      t.decimal :value, null: false, precision: 30, scale: 15
+      # Move to Measurement?
       #t.references :collector, foreign_key: true
       #t.references :device, foreign_key: true
 

lib/tasks/test_databases.rake

@@ -0,0 +1,158 @@
+require 'yaml'
+require 'erb'
+require 'tmpdir'
+
+# Multi-database test runner
+# ==========================
+# When database.yml contains more than one `test*` configuration, every
+# standard test task (test, test:models, test:system, …) is automatically
+# rewritten to run the full suite against EACH configured database in turn.
+#
+# Convention — any top-level key that starts with "test" and holds a Hash:
+#
+#   test:           ← required primary database
+#     adapter: mysql2
+#     database: fixinme_test
+#     ...
+#
+#   test_sqlite:    ← optional additional databases
+#     adapter: sqlite3
+#     database: db/fixinme_test.sqlite3
+#
+#   test_pg:
+#     adapter: postgresql
+#     ...
+#
+# A single-database setup is unchanged: every task behaves exactly as before.
+#
+# The mechanism uses RAILS_DATABASE_YML — an env var read by
+# config/application.rb(.dist) to override Rails' database config path before
+# initialisation, giving each subprocess a clean, isolated database config.
+
+module MultiDbTests
+  ADAPTER_GEMS = {
+    'mysql2'      => 'mysql2',
+    'sqlite3'     => 'sqlite3',
+    'postgresql'  => 'pg',
+    'pg'          => 'pg',
+  }.freeze
+
+  ADAPTER_BUNDLE_GROUPS = {
+    'mysql2'      => 'mysql',
+    'sqlite3'     => 'sqlite',
+    'postgresql'  => 'postgresql',
+    'pg'          => 'postgresql',
+  }.freeze
+
+  # Rake task names generated by railties/lib/rails/test_unit/testing.rake
+  # that use run_from_rake — these are the ones we rewrite.
+  WRAPPED_TASKS = (
+    ['test'] +
+    Rails::TestUnit::Runner::TEST_FOLDERS.map { |f| "test:#{f}" } +
+    %w[test:all test:system test:generators test:units test:functionals]
+  ).freeze
+
+  class << self
+    # Returns {name => config_hash} for every key starting with "test".
+    def test_configs
+      @test_configs ||= begin
+        db_file = Rails.root.join('config', 'database.yml')
+        all     = YAML.safe_load(ERB.new(db_file.read).result, aliases: true) || {}
+        all.select { |k, v| k.to_s.start_with?('test') && v.is_a?(Hash) }
+      end
+    end
+
+    def non_test_configs
+      @non_test_configs ||= begin
+        db_file = Rails.root.join('config', 'database.yml')
+        all     = YAML.safe_load(ERB.new(db_file.read).result, aliases: true) || {}
+        all.reject { |k, _| k.to_s.start_with?('test') }
+      end
+    end
+
+    # Run rails +task_name+ for every configured test database.
+    # Called from the rewritten rake task actions.
+    def run(task_name)
+      cfgs    = test_configs
+      results = {}
+
+      cfgs.each do |db_name, config|
+        adapter = config['adapter'].to_s
+        puts "\n#{'─' * 64}"
+        puts "  #{task_name}  ·  #{db_name}  (#{adapter})"
+        puts '─' * 64
+
+        unless adapter_available?(adapter)
+          warn "  SKIPPED — '#{adapter}' gem not in bundle.\n" \
+               "  Run: bundle config --local with \"#{current_with} #{adapter_group(adapter)}\""
+          results[db_name] = :skipped
+          next
+        end
+
+        Dir.mktmpdir('rails_test_') do |tmpdir|
+          tmp_yml = File.join(tmpdir, 'database.yml')
+          File.write(tmp_yml, non_test_configs.merge('test' => config).to_yaml)
+          env = { 'RAILS_DATABASE_YML' => tmp_yml }
+
+          if system(env, 'bundle exec rails db:test:prepare')
+            results[db_name] = system(env, 'rails', task_name) ? :pass : :fail
+          else
+            results[db_name] = :prepare_failed
+          end
+        end
+      end
+
+      print_summary(cfgs, results)
+
+      failed = results.count { |_, s| [:fail, :prepare_failed].include?(s) }
+      exit(false) if failed > 0
+    end
+
+    private
+
+    def adapter_available?(adapter)
+      require ADAPTER_GEMS.fetch(adapter, adapter)
+      true
+    rescue LoadError
+      false
+    end
+
+    def adapter_group(adapter)
+      ADAPTER_BUNDLE_GROUPS.fetch(adapter, adapter)
+    end
+
+    def current_with
+      (Bundler.settings[:with] || '').split(':').join(' ')
+    end
+
+    def print_summary(cfgs, results)
+      return if results.size <= 1  # no summary for single-DB runs
+
+      puts "\n#{'═' * 64}"
+      puts '  SUMMARY'
+      puts '═' * 64
+      results.each do |db_name, status|
+        adapter = cfgs.dig(db_name, 'adapter') || '?'
+        icon    = status == :pass ? '✓' : (status == :skipped ? '–' : '✗')
+        label   = { pass: 'PASS', fail: 'FAIL',
+                    prepare_failed: 'PREPARE FAILED', skipped: 'SKIPPED' }[status]
+        puts "  #{icon}  #{db_name.ljust(26)} (#{adapter.ljust(12)})  #{label}"
+      end
+      puts '═' * 64
+    end
+  end
+end
+
+# Rewrite every standard test task to run against all configured databases.
+# This file loads after railties/testing.rake, so all tasks already exist.
+# Single-database setups are completely unaffected.
+if MultiDbTests.test_configs.size > 1
+  MultiDbTests::WRAPPED_TASKS.each do |task_name|
+    next unless Rake::Task.task_defined?(task_name)
+
+    Rake::Task[task_name].clear_actions
+    Rake::Task[task_name].enhance do
+      MultiDbTests.run(task_name)
+    end
+  end
+end