add app test suite — unit, widget, golden, a11y (168 tests)

Four layers under app/test/:

  * kernel/, extension/ — unit tests for every kernel service and
    the extension contract. i18n fallback chain gets the full
    matrix (exact/lang/default/placeholder, namespace isolation,
    unknown namespace, interpolation). Theme resolver and
    extension-manager topo sort covered.
  * widgets/, builtin/ — widget tests for every primitive and each
    Tier 0 built-in. Assertions reach into the Semantics node so
    a missing label fails structurally, not visually.
  * goldens/ — Alchemist + Ahem font for cross-platform pixel
    stability; primitives only (button, tab bar, icon set). No
    goldens for compositions — they'd churn through every tier.
  * a11y/ — contract-level gate: semantic coverage walks the
    built-in catalogue, contrast walks every token pair in every
    bundled theme against WCAG-AA thresholds (catches real
    regressions: the first run caught `tab.inactive_text` at 2.81
    in summer-night), i18n coverage asserts every referenced key
    exists in its catalog (exists-in-map, not "key == value" — too
    ambiguous for keys that happen to equal their translation).

Helpers under helpers/: `KernelFixture.create()` boots a
KernelServices with in-memory stores + a FakeDaemonClient (no
socket, drivable connected-state), `widget_harness` wraps a
widget in the minimum tree that resolves theme + i18n.

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

app/test/kernel/src/panels/arrangement_test.dart

@@ -0,0 +1,50 @@
+import 'package:clide_app/kernel/kernel.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  group('LayoutArrangement', () {
+    test('applyPreset sets position + size + visibility per slot', () {
+      final a = LayoutArrangement();
+      a.applyPreset(classicPreset());
+      expect(a.positionOf(Slots.sidebar), SlotPosition.left);
+      expect(a.sizeOf(Slots.sidebar), 240);
+      expect(a.minSizeOf(Slots.sidebar), 180);
+      expect(a.maxSizeOf(Slots.sidebar), 400);
+      expect(a.isVisible(Slots.workspace), true);
+    });
+
+    test('setSize clamps to min/max', () {
+      final a = LayoutArrangement()..applyPreset(classicPreset());
+      a.setSize(Slots.sidebar, 50); // below min 180
+      expect(a.sizeOf(Slots.sidebar), 180);
+      a.setSize(Slots.sidebar, 10000); // above max 400
+      expect(a.sizeOf(Slots.sidebar), 400);
+    });
+
+    test('setSize notifies listeners only when changing', () {
+      final a = LayoutArrangement()..applyPreset(classicPreset());
+      var count = 0;
+      a.addListener(() => count++);
+      a.setSize(Slots.sidebar, 240); // already 240, no change
+      expect(count, 0);
+      a.setSize(Slots.sidebar, 260);
+      expect(count, 1);
+    });
+
+    test('setVisible flips the flag', () {
+      final a = LayoutArrangement()..applyPreset(classicPreset());
+      expect(a.isVisible(Slots.sidebar), true);
+      a.setVisible(Slots.sidebar, false);
+      expect(a.isVisible(Slots.sidebar), false);
+    });
+
+    test('registerSlotsInto populates a PanelRegistry', () {
+      final a = LayoutArrangement();
+      final r = PanelRegistry();
+      final preset = classicPreset();
+      a.registerSlotsInto(r, preset);
+      expect(r.definitionFor(Slots.sidebar), isNotNull);
+      expect(r.definitionFor(Slots.statusbar), isNotNull);
+    });
+  });
+}

app/test/kernel/src/panels/registry_test.dart

@@ -0,0 +1,76 @@
+import 'package:clide_app/extension/extension.dart';
+import 'package:clide_app/kernel/kernel.dart';
+import 'package:flutter/widgets.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+TabContribution _tab({
+  required String id,
+  required SlotId slot,
+  int priority = 0,
+}) =>
+    TabContribution(
+      id: id,
+      slot: slot,
+      title: id,
+      priority: priority,
+      build: (_) => const SizedBox.shrink(),
+    );
+
+void main() {
+  group('PanelRegistry', () {
+    late PanelRegistry r;
+
+    setUp(() => r = PanelRegistry());
+
+    test('registerSlot creates an empty mount list', () {
+      r.registerSlot(const SlotDefinition(
+        id: Slots.sidebar,
+        position: SlotPosition.left,
+      ));
+      expect(r.definitionFor(Slots.sidebar)!.position, SlotPosition.left);
+      expect(r.contributionsFor(Slots.sidebar), isEmpty);
+    });
+
+    test('contribute appends to the slot and orders by priority', () {
+      r.contribute(_tab(id: 'a', slot: Slots.sidebar, priority: 10));
+      r.contribute(_tab(id: 'b', slot: Slots.sidebar, priority: -5));
+      r.contribute(_tab(id: 'c', slot: Slots.sidebar, priority: 0));
+      expect(r.tabsFor(Slots.sidebar).map((t) => t.id), ['b', 'c', 'a']);
+    });
+
+    test('first tab contribution becomes the active tab', () {
+      r.contribute(_tab(id: 'a', slot: Slots.sidebar));
+      expect(r.activeTabIn(Slots.sidebar), 'a');
+      r.contribute(_tab(id: 'b', slot: Slots.sidebar));
+      expect(r.activeTabIn(Slots.sidebar), 'a');
+    });
+
+    test('uncontribute removes by id and reassigns active tab', () {
+      r.contribute(_tab(id: 'a', slot: Slots.sidebar));
+      r.contribute(_tab(id: 'b', slot: Slots.sidebar));
+      expect(r.activeTabIn(Slots.sidebar), 'a');
+      r.uncontribute('a');
+      expect(r.tabsFor(Slots.sidebar).map((t) => t.id), ['b']);
+      expect(r.activeTabIn(Slots.sidebar), 'b');
+    });
+
+    test('activateTab notifies listeners', () {
+      r.contribute(_tab(id: 'a', slot: Slots.sidebar));
+      r.contribute(_tab(id: 'b', slot: Slots.sidebar));
+      var count = 0;
+      r.addListener(() => count++);
+      r.activateTab(Slots.sidebar, 'b');
+      expect(r.activeTabIn(Slots.sidebar), 'b');
+      expect(count, 1);
+    });
+
+    test('contributing a non-slot contribution is a no-op for slots', () {
+      r.contribute(CommandContribution(
+        id: 'c',
+        command: 'c',
+        run: (_) async => throw UnimplementedError(),
+      ));
+      expect(r.tabsFor(Slots.sidebar), isEmpty);
+    });
+  });
+}