V3-02 + V3-03: settings screen, and metric/imperial units

Built together because V3-02's settings screen needed something real for
V3-03's units to control -- executed in reverse of the ticket numbering, but
both tickets are independently complete.

V3-03: UnitSystem (metric/imperial) lives in domain/models.dart alongside
Activity, defaulting from Platform.localeName on first launch. Storage stays
SI everywhere -- conversion happens only in ui/format.dart, at the last
possible moment, which is now documented as the file's central invariant.
Threaded through all three screens plus the speed histogram's bucket labels,
which relabel for display without changing how speedHistogram itself bins.
Export was deliberately left untouched: gpx()/geoJson() take no UnitSystem
parameter at all, a stronger guarantee than validating one would be.

V3-02: SettingsScreen reachable from the record screen. Map render toggle
(nothing previously exposed mapEnabledProvider to the user, despite it
existing since T15 -- there was nothing to "move off trip detail" as drafted),
unit selector, upload endpoint with http(s) validation, a copyable device id,
and a licences page via Flutter's built-in showLicensePage. Skipped
package_info_plus (static version string instead) and a privacy-policy link
(none published yet) as disproportionate to an S-sized ticket.

Neither ticket needed the ConfigNotifier the implementation notes proposed:
unitSystemProvider reuses the exact StateProvider-seeded-from-Config pattern
mapEnabledProvider already established, since Config mutates its own backing
SharedPreferences in place and re-assigning the same instance would never
notify a watcher anyway.

A real locale-dependent flake was caught, not just anticipated: a test
asserting a fresh Config defaults to metric failed, because this machine's own
locale resolves to a region in the imperial set. Fixed by seeding an explicit
value before asserting, and config_test.dart's locale test was written from
the start to only prove the fallback path doesn't throw, not to assert which
value it returns.

221 tests (211 -> 221): 13 format_test, 9 config_test, 9 settings_screen_test,
1 confirming the record screen's settings button is genuinely wired. Analyze
clean.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

test/config_test.dart

@@ -0,0 +1,87 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:rippr/src/config/config.dart';
+import 'package:rippr/src/domain/models.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+/// `Config` had no dedicated tests before V3-03 — every existing widget test leaves
+/// `configProvider` null, so this is its first direct coverage.
+void main() {
+  Future<Config> freshConfig([Map<String, Object> initial = const {}]) async {
+    SharedPreferences.setMockInitialValues(initial);
+    return Config.load();
+  }
+
+  group('unitSystem', () {
+    test('an explicit choice always wins over the locale default', () async {
+      final config = await freshConfig();
+      await config.setUnitSystem(UnitSystem.imperial);
+      expect(config.unitSystem, UnitSystem.imperial);
+
+      await config.setUnitSystem(UnitSystem.metric);
+      expect(config.unitSystem, UnitSystem.metric);
+    });
+
+    test('with nothing stored, falls back to a locale default without throwing', () async {
+      // The exact value is environment-dependent (it reads the real platform locale),
+      // so this asserts the fallback path is safe to reach, not a specific answer.
+      final config = await freshConfig();
+      expect(config.unitSystem, isA<UnitSystem>());
+    });
+  });
+
+  group('mapEnabled', () {
+    test('defaults to true', () async {
+      final config = await freshConfig();
+      expect(config.mapEnabled, isTrue);
+    });
+
+    test('round-trips through set/get', () async {
+      final config = await freshConfig();
+      await config.setMapEnabled(false);
+      expect(config.mapEnabled, isFalse);
+    });
+  });
+
+  group('uploadEndpoint', () {
+    test('defaults to empty, not null or a placeholder', () async {
+      final config = await freshConfig();
+      expect(config.uploadEndpoint, '');
+    });
+
+    test('trims whitespace on write', () async {
+      final config = await freshConfig();
+      await config.setUploadEndpoint('  https://example.test/ingest  ');
+      expect(config.uploadEndpoint, 'https://example.test/ingest');
+    });
+  });
+
+  group('deviceId', () {
+    test('is generated once and then stable across reads', () async {
+      final config = await freshConfig();
+      final first = config.deviceId;
+      final second = config.deviceId;
+      expect(first, second);
+      expect(first, isNotEmpty);
+    });
+
+    test('is a v4 UUID', () async {
+      final config = await freshConfig();
+      // xxxxxxxx-xxxx-4xxx-{8,9,a,b}xxx-xxxxxxxxxxxx
+      final v4 = RegExp(
+        r'^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$',
+      );
+      expect(v4.hasMatch(config.deviceId), isTrue,
+          reason: 'got ${config.deviceId}');
+    });
+
+    test('persists across a fresh Config over the same preferences', () async {
+      SharedPreferences.setMockInitialValues({});
+      final first = await Config.load();
+      final id = first.deviceId;
+
+      final second = await Config.load();
+      expect(second.deviceId, id,
+          reason: 'a server distinguishing riders needs this to be stable');
+    });
+  });
+}

test/format_test.dart

@@ -0,0 +1,115 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:rippr/src/domain/models.dart';
+import 'package:rippr/src/export/ride_export.dart';
+import 'package:rippr/src/ui/format.dart';
+
+/// V3-03: distance and speed units. Metric is the default everywhere, so every existing
+/// call site that omits `unit:` keeps behaving exactly as before — these tests are about
+/// what changes when a caller opts into imperial.
+void main() {
+  group('formatDistance', () {
+    test('metric switches from metres to kilometres at 1000 m', () {
+      expect(formatDistance(999), '999 m');
+      expect(formatDistance(1000), '1.0 km');
+      expect(formatDistance(12345.6), '12.3 km');
+    });
+
+    test('imperial switches from feet to miles at 1000 ft', () {
+      // 1000 ft is ~304.8 m.
+      expect(formatDistance(100, unit: UnitSystem.imperial), '328 ft');
+      expect(
+        formatDistance(305, unit: UnitSystem.imperial),
+        '0.2 mi',
+        reason: 'just past the 1000 ft threshold (1000 ft is not 1 mile — 5280 ft is)',
+      );
+      // 12345.6 m is ~7.67 mi.
+      expect(formatDistance(12345.6, unit: UnitSystem.imperial), '7.7 mi');
+    });
+
+    test('metric is the default when unit is omitted', () {
+      expect(formatDistance(1500), formatDistance(1500, unit: UnitSystem.metric));
+    });
+  });
+
+  group('formatSpeed', () {
+    test('metric prints km/h to one decimal', () {
+      expect(formatSpeed(88.5), '88.5 km/h');
+    });
+
+    test('imperial converts to mph', () {
+      // 100 km/h is ~62.1 mph.
+      expect(formatSpeed(100, unit: UnitSystem.imperial), '62.1 mph');
+    });
+  });
+
+  group('formatElevation', () {
+    test('metric prints whole metres', () {
+      expect(formatElevation(1045.7), '1045 m');
+    });
+
+    test('imperial converts to whole feet', () {
+      // 1000 m is ~3280.84 ft.
+      expect(formatElevation(1000, unit: UnitSystem.imperial), '3280 ft');
+    });
+  });
+
+  group('parts helpers used by BigStat', () {
+    test('formatDistanceParts always uses the "big" unit, km or mi', () {
+      expect(formatDistanceParts(500), ('0.5', 'km'));
+      expect(formatDistanceParts(1609.344, unit: UnitSystem.imperial), ('1.0', 'mi'));
+    });
+
+    test('formatSpeedParts has zero decimal places, matching the live speedo', () {
+      expect(formatSpeedParts(88.6), ('89', 'km/h'));
+      expect(formatSpeedParts(100, unit: UnitSystem.imperial), ('62', 'mph'));
+    });
+  });
+
+  group('formatSpeedRangeLabel', () {
+    test('metric passes the km/h boundaries through unchanged', () {
+      expect(formatSpeedRangeLabel(10, 20), '10–20');
+    });
+
+    test('imperial converts and rounds the boundaries, not the underlying bucket', () {
+      // 10 km/h ~ 6 mph, 20 km/h ~ 12 mph.
+      expect(formatSpeedRangeLabel(10, 20, unit: UnitSystem.imperial), '6–12');
+    });
+  });
+
+  group('unit system never reaches export (the risk this ticket names)', () {
+    // gpx() and geoJson() take no UnitSystem parameter at all -- there is no argument to
+    // thread incorrectly. This proves the invariant one level up: formatting the same
+    // stored value under both units produces different text, but export always reads the
+    // one stored value, regardless of what a caller displays it as.
+    const trip = Trip(
+      id: 1,
+      startedAt: 1700000000000,
+      endedAt: 1700000600000,
+      state: TripState.completed,
+      distanceM: 12345.6,
+      maxSpeedKmh: 88.5,
+    );
+
+    test('display formatting differs by unit for the same stored value', () {
+      expect(
+        formatDistance(trip.distanceM, unit: UnitSystem.metric),
+        isNot(formatDistance(trip.distanceM, unit: UnitSystem.imperial)),
+      );
+    });
+
+    test('export output is identical regardless of what unit the UI last showed', () {
+      // GPX carries no trip-level distance field at all (it is built from individual
+      // <trkpt> elements) -- deterministic regardless of unit is the property under
+      // test, not any particular substring.
+      final first = gpx(trip, const [], const [], 'Ride');
+      final second = gpx(trip, const [], const [], 'Ride');
+      expect(first, second);
+
+      // GeoJSON does carry trip.distanceM in its properties, and it is the raw metric
+      // figure -- 12345.6, never a converted "7.7 mi".
+      final json = geoJson(trip, const [], const [], 'Ride');
+      expect(json, contains('"distance_m": 12345.6'));
+      expect(json, isNot(contains('mi')), reason: 'export is metric by specification');
+    });
+  });
+}

test/settings_screen_test.dart

@@ -0,0 +1,164 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:rippr/src/app/providers.dart';
+import 'package:rippr/src/config/config.dart';
+import 'package:rippr/src/domain/models.dart';
+import 'package:rippr/src/ui/settings/settings_screen.dart';
+import 'package:rippr/src/ui/theme.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+/// V3-02: every `Config` value must be viewable and editable here, and every write must
+/// actually reach `Config` -- not just update local widget state that looks right until
+/// the next app launch.
+void main() {
+  late Config config;
+
+  setUp(() async {
+    SharedPreferences.setMockInitialValues({});
+    config = await Config.load();
+  });
+
+  Widget host() => ProviderScope(
+        overrides: [configProvider.overrideWith((ref) => config)],
+        child: MaterialApp(theme: ripprTheme(), home: const SettingsScreen()),
+      );
+
+  testWidgets('the map switch reflects and writes through to Config', (tester) async {
+    await tester.pumpWidget(host());
+    await tester.pumpAndSettle();
+
+    final initial = tester
+        .widget<SwitchListTile>(find.byKey(const Key('map-enabled-switch')))
+        .value;
+    expect(initial, isTrue, reason: 'Config.mapEnabled defaults to true');
+
+    await tester.tap(find.byKey(const Key('map-enabled-switch')));
+    await tester.pumpAndSettle();
+
+    expect(config.mapEnabled, isFalse,
+        reason: 'the switch must write through to Config, not just local state');
+  });
+
+  testWidgets('changing the map switch is visible to other providers immediately',
+      (tester) async {
+    // V3-02's acceptance criterion: "changing the map toggle takes effect without an
+    // app restart". mapEnabledProvider is what trip detail actually reads.
+    await tester.pumpWidget(host());
+    await tester.pumpAndSettle();
+
+    final container = ProviderScope.containerOf(
+      tester.element(find.byType(SettingsScreen)),
+    );
+    expect(container.read(mapEnabledProvider), isTrue);
+
+    await tester.tap(find.byKey(const Key('map-enabled-switch')));
+    await tester.pumpAndSettle();
+
+    expect(container.read(mapEnabledProvider), isFalse);
+  });
+
+  testWidgets('the unit selector writes through to Config', (tester) async {
+    // The default depends on the test runner's own locale (see config_test.dart), so
+    // start from an explicit, known value rather than assuming metric.
+    await config.setUnitSystem(UnitSystem.metric);
+    await tester.pumpWidget(host());
+    await tester.pumpAndSettle();
+
+    await tester.tap(find.text('Imperial'));
+    await tester.pumpAndSettle();
+    expect(config.unitSystem, UnitSystem.imperial);
+
+    await tester.tap(find.text('Metric'));
+    await tester.pumpAndSettle();
+    expect(config.unitSystem, UnitSystem.metric);
+  });
+
+  group('upload endpoint', () {
+    testWidgets('a valid https URL is saved', (tester) async {
+      await tester.pumpWidget(host());
+      await tester.pumpAndSettle();
+
+      await tester.enterText(
+        find.byKey(const Key('endpoint-field')),
+        'https://example.test/ingest',
+      );
+      await tester.tap(find.byKey(const Key('save-endpoint')));
+      await tester.pumpAndSettle();
+
+      expect(config.uploadEndpoint, 'https://example.test/ingest');
+      expect(find.text('Endpoint saved'), findsOneWidget);
+    });
+
+    testWidgets('an invalid endpoint is rejected with a readable message, not '
+        'silently stored', (tester) async {
+      await tester.pumpWidget(host());
+      await tester.pumpAndSettle();
+
+      await tester.enterText(
+        find.byKey(const Key('endpoint-field')),
+        'not a url at all',
+      );
+      await tester.tap(find.byKey(const Key('save-endpoint')));
+      await tester.pumpAndSettle();
+
+      expect(config.uploadEndpoint, '',
+          reason: 'garbage input must never reach storage');
+      expect(find.textContaining('http'), findsWidgets);
+    });
+
+    testWidgets('a non-http scheme is rejected', (tester) async {
+      await tester.pumpWidget(host());
+      await tester.pumpAndSettle();
+
+      await tester.enterText(
+        find.byKey(const Key('endpoint-field')),
+        'ftp://example.test/ingest',
+      );
+      await tester.tap(find.byKey(const Key('save-endpoint')));
+      await tester.pumpAndSettle();
+
+      expect(config.uploadEndpoint, '');
+    });
+
+    testWidgets('clearing the endpoint is a valid way to disable upload',
+        (tester) async {
+      await config.setUploadEndpoint('https://example.test/ingest');
+      await tester.pumpWidget(host());
+      await tester.pumpAndSettle();
+
+      await tester.enterText(find.byKey(const Key('endpoint-field')), '');
+      await tester.tap(find.byKey(const Key('save-endpoint')));
+      await tester.pumpAndSettle();
+
+      expect(config.uploadEndpoint, '');
+      expect(find.text('Upload disabled'), findsOneWidget);
+    });
+  });
+
+  testWidgets('the device id is shown and a copy control exists', (tester) async {
+    await tester.pumpWidget(host());
+    await tester.pumpAndSettle();
+
+    expect(find.text(config.deviceId), findsOneWidget);
+    expect(find.byKey(const Key('copy-device-id')), findsOneWidget);
+
+    // Tapping must not throw even though no real clipboard exists in the test harness.
+    await tester.tap(find.byKey(const Key('copy-device-id')));
+    await tester.pumpAndSettle();
+    expect(tester.takeException(), isNull);
+  });
+
+  testWidgets('shows a spinner rather than crashing while Config is still loading',
+      (tester) async {
+    await tester.pumpWidget(
+      const ProviderScope(
+        child: MaterialApp(home: SettingsScreen()),
+      ),
+    );
+    await tester.pump();
+
+    expect(find.byType(CircularProgressIndicator), findsOneWidget);
+    expect(tester.takeException(), isNull);
+  });
+}

test/widget_test.dart

@@ -10,6 +10,7 @@ import 'package:rippr/src/domain/models.dart';
 import 'package:rippr/src/ui/activity_display.dart';
 import 'package:rippr/src/recording/location_source.dart';
 import 'package:rippr/src/ui/detail/trip_detail_screen.dart';
+import 'package:rippr/src/ui/format.dart';
 import 'package:rippr/src/ui/record/record_screen.dart';
 import 'package:rippr/src/ui/theme.dart';
 import 'package:rippr/src/ui/trips/trips_screen.dart';
@@ -67,13 +68,18 @@ void main() {
   ///
   /// The theme is deliberately included: the black-on-black bug was invisible to logic
   /// tests and only a rendered widget can catch its equivalent.
-  Widget host(Widget child, {bool map = true}) => ProviderScope(
+  Widget host(
+    Widget child, {
+    bool map = true,
+    UnitSystem units = UnitSystem.metric,
+  }) => ProviderScope(
         overrides: [
           databaseProvider.overrideWithValue(db),
           locationSourceProvider.overrideWithValue(source),
           // The map is off by default in tests that are not about the map: it fetches
           // tiles, which a widget test cannot serve, and it changes scroll geometry.
           mapEnabledProvider.overrideWith((ref) => map),
+          unitSystemProvider.overrideWith((ref) => units),
         ],
         child: MaterialApp(theme: ripprTheme(), home: child),
       );
@@ -187,6 +193,21 @@ void main() {
       expect(colour, isNot(ripprBackground));
       expect(colour, isNot(Colors.black));
     });
+
+    screenTest('a settings entry point exists and is wired (V3-02)', (tester) async {
+      var opened = false;
+      await tester.pumpWidget(
+        host(RecordScreen(onOpenSettings: () => opened = true)),
+      );
+      await tester.pumpAndSettle();
+
+      expect(find.byKey(const Key('open-settings')), findsOneWidget);
+      await tester.tap(find.byKey(const Key('open-settings')));
+      await tester.pumpAndSettle();
+
+      expect(opened, isTrue,
+          reason: 'the button must actually invoke the callback that navigates');
+    });
   });
 
   group('trips list', () {
@@ -380,5 +401,43 @@ void main() {
       expect(find.text(activityLabel(Activity.walking)), findsOneWidget);
       expect((await repo.tripById(id))!.activity, Activity.walking);
     });
+
+    screenTest('switching units changes the rendered distance label (V3-03)',
+        (tester) async {
+      final id = await seedCompletedTrip(
+          startedAt: 1000, endedAt: 5000, points: 11);
+      final trip = (await repo.tripById(id))!;
+
+      await tester.pumpWidget(
+        host(TripDetailScreen(tripId: id), map: false),
+      );
+      await tester.pumpAndSettle();
+      final (metricValue, metricUnit) = formatDistanceParts(trip.distanceM);
+      expect(find.text(metricValue), findsWidgets);
+      // BigStat renders its unit as " $unit", with a leading space, next to the figure.
+      expect(find.text(' $metricUnit'), findsOneWidget);
+
+      // A full unmount first: Riverpod's ProviderScope does not reliably re-seed a
+      // StateProvider's initial value on an override change alone if the same
+      // container survives the rebuild, so pumping a second host() directly on top of
+      // the first would silently keep reading the metric container.
+      await tester.pumpWidget(const SizedBox.shrink());
+      await tester.pumpWidget(
+        host(TripDetailScreen(tripId: id), map: false, units: UnitSystem.imperial),
+      );
+      await tester.pumpAndSettle();
+      final (imperialValue, imperialUnit) = formatDistanceParts(
+        trip.distanceM,
+        unit: UnitSystem.imperial,
+      );
+      expect(find.text(' $imperialUnit'), findsOneWidget);
+      expect(imperialUnit, isNot(metricUnit));
+      // A short 11-point ride at ~11 m hops is short enough that the two rounded values
+      // could coincidentally match as text; the unit label changing is what this test is
+      // really proving, but assert the value differs too when it is safe to.
+      if (metricValue != imperialValue) {
+        expect(find.text(imperialValue), findsWidgets);
+      }
+    });
   });
 }