fix decision first-click + editor reveal via retained reader nav

Two reveal-on-open bugs:

Decisions opened only on the second click (T-196): the detail view
subscribed in didChangeDependencies, which runs after the tab is
revealed, so the broadcast 'selection' that triggered the reveal was
already gone. Hoist the back/forward history out of per-view State into
a retained per-reader ReaderNav (kernel ChangeNotifier in a
ReaderNavRegistry, D-81). The nav records selections, emits 'load' (the
single channel readers display from), and survives mount/unmount — the
reader grabs nav.current on mount, so the first selection lands. Both
the markdown and decisions readers move to this model; the per-view
ReaderHistoryMixin and the markdown post-frame forward hack are gone.

The editor pane never opened (T-197): EditorExtension contributed a
workspace tab but nothing activated it on editor.open. Add an activate()
that reveals the tab on editor.opened / editor.active-changed; the
view's hydrate() pulls the active buffer on mount.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

test/builtin/decisions/decision_reader_test.dart

@@ -89,7 +89,13 @@ void main() {
       f = await KernelFixture.create();
       await _bootExtension(f);
     });
-    tearDown(() => f.dispose());
+    tearDown(() async {
+      // Deactivate before dispose so any post-frame forward scheduled by
+      // these (non-pumping) tests is neutralised — otherwise it fires in
+      // a later testWidgets against a torn-down bus.
+      await f.services.extensions.deactivate('builtin.decisions');
+      await f.dispose();
+    });
 
     test('activate contributes decisions.detail as a static tab', () {
       final tabs = f.services.panels.tabsFor(Slots.contextPanel);
@@ -237,8 +243,9 @@ void main() {
       // Starts empty.
       expect(find.text('Select a decision to view details.'), findsOneWidget);
 
-      // Publish a selection.
-      f.services.messages.publish('builtin.decisions', 'selection', {'id': 'D-7'});
+      // The view loads on 'load' (forwarded by the extension post-frame
+      // after it reveals the tab; T-196).
+      f.services.messages.publish('builtin.decisions', 'load', {'id': 'D-7'});
       // Give the broadcast stream a microtask to deliver.
       await pumpAsync(tester);
 
@@ -251,7 +258,7 @@ void main() {
       await pumpView(tester, initialId: 'D-1');
       expect(find.text('Decision D-1'), findsWidgets);
 
-      f.services.messages.publish('builtin.decisions', 'selection', {'id': 'D-2'});
+      f.services.messages.publish('builtin.decisions', 'load', {'id': 'D-2'});
       await pumpAsync(tester);
 
       expect(find.text('Decision D-2'), findsWidgets);
@@ -262,7 +269,7 @@ void main() {
       await pumpView(tester, initialId: 'D-5');
       expect(find.text('Decision D-5'), findsWidgets);
 
-      f.services.messages.publish('builtin.decisions', 'selection', {'id': 'D-5'});
+      f.services.messages.publish('builtin.decisions', 'load', {'id': 'D-5'});
       await pumpAsync(tester);
 
       // Still shows D-5, no crash.
@@ -273,7 +280,7 @@ void main() {
       await pumpView(tester);
 
       for (var i = 1; i <= 5; i++) {
-        f.services.messages.publish('builtin.decisions', 'selection', {'id': 'D-$i'});
+        f.services.messages.publish('builtin.decisions', 'load', {'id': 'D-$i'});
       }
       await pumpAsync(tester);
 
@@ -541,6 +548,13 @@ void main() {
     });
     tearDown(() => f.dispose());
 
+    // Drive the retained nav (the history source); its 'load' emit makes
+    // the mounted view display the entry (T-196).
+    Future<void> open(WidgetTester tester, String id) async {
+      f.services.readerNav.navFor('builtin.decisions', dataKey: 'id').open(id);
+      await pumpAsync(tester);
+    }
+
     Future<void> pumpView(WidgetTester tester, {String? initialId}) async {
       tester.view.physicalSize = const Size(600, 800);
       tester.view.devicePixelRatio = 1.0;
@@ -548,8 +562,9 @@ void main() {
         tester.view.resetPhysicalSize();
         tester.view.resetDevicePixelRatio();
       });
-      await tester.pumpWidget(harness(f, DecisionDetailView(initialId: initialId)));
+      await tester.pumpWidget(harness(f, const DecisionDetailView()));
       await pumpAsync(tester);
+      if (initialId != null) await open(tester, initialId);
     }
 
     testWidgets('back disabled on initial load', (tester) async {
@@ -565,8 +580,7 @@ void main() {
 
     testWidgets('back enabled after two selections', (tester) async {
       await pumpView(tester, initialId: 'D-1');
-      f.services.messages.publish('builtin.decisions', 'selection', {'id': 'D-2'});
-      await pumpAsync(tester);
+      await open(tester, 'D-2');
 
       expect(
         find.byWidgetPredicate(
@@ -578,8 +592,7 @@ void main() {
 
     testWidgets('back navigates to previous decision', (tester) async {
       await pumpView(tester, initialId: 'D-1');
-      f.services.messages.publish('builtin.decisions', 'selection', {'id': 'D-2'});
-      await pumpAsync(tester);
+      await open(tester, 'D-2');
       // Title appears in pane header subtitle + body card.
       expect(find.text('Decision D-2'), findsWidgets);
 
@@ -594,14 +607,13 @@ void main() {
 
     testWidgets('back/forward does NOT re-publish selection bus event', (tester) async {
       await pumpView(tester, initialId: 'D-1');
-      f.services.messages.publish('builtin.decisions', 'selection', {'id': 'D-2'});
-      await pumpAsync(tester);
+      await open(tester, 'D-2');
 
       final selections = <Message>[];
       final sub = f.services.messages.subscribe(publisher: 'builtin.decisions', channel: 'selection').listen(selections.add);
       addTearDown(sub.cancel);
 
-      // Go back — should NOT publish a selection message.
+      // Go back — re-emits on 'load', NOT 'selection'.
       final backBtn = find.byWidgetPredicate(
         (w) => w is Semantics && w.properties.label == 'Back' && (w.properties.enabled ?? true),
       );
@@ -613,8 +625,7 @@ void main() {
 
     testWidgets('forward disabled at end of history', (tester) async {
       await pumpView(tester, initialId: 'D-1');
-      f.services.messages.publish('builtin.decisions', 'selection', {'id': 'D-2'});
-      await pumpAsync(tester);
+      await open(tester, 'D-2');
 
       expect(
         find.byWidgetPredicate(
@@ -626,8 +637,7 @@ void main() {
 
     testWidgets('forward navigates after back', (tester) async {
       await pumpView(tester, initialId: 'D-1');
-      f.services.messages.publish('builtin.decisions', 'selection', {'id': 'D-2'});
-      await pumpAsync(tester);
+      await open(tester, 'D-2');
 
       // Go back to D-1.
       final backBtn = find.byWidgetPredicate(
@@ -648,8 +658,7 @@ void main() {
 
     testWidgets('new selection truncates forward history', (tester) async {
       await pumpView(tester, initialId: 'D-1');
-      f.services.messages.publish('builtin.decisions', 'selection', {'id': 'D-2'});
-      await pumpAsync(tester);
+      await open(tester, 'D-2');
 
       // Go back to D-1.
       final backBtn = find.byWidgetPredicate(
@@ -658,9 +667,8 @@ void main() {
       await tester.tap(backBtn.first);
       await pumpAsync(tester);
 
-      // Load D-3 — truncates D-2 forward history.
-      f.services.messages.publish('builtin.decisions', 'selection', {'id': 'D-3'});
-      await pumpAsync(tester);
+      // Open D-3 — truncates D-2 forward history.
+      await open(tester, 'D-3');
 
       expect(
         find.byWidgetPredicate(
@@ -687,6 +695,11 @@ void main() {
     });
     tearDown(() => f.dispose());
 
+    Future<void> open(WidgetTester tester, String id) async {
+      f.services.readerNav.navFor('builtin.decisions', dataKey: 'id').open(id);
+      await pumpAsync(tester);
+    }
+
     Future<void> pumpView(WidgetTester tester, {String? initialId}) async {
       tester.view.physicalSize = const Size(600, 800);
       tester.view.devicePixelRatio = 1.0;
@@ -694,8 +707,9 @@ void main() {
         tester.view.resetPhysicalSize();
         tester.view.resetDevicePixelRatio();
       });
-      await tester.pumpWidget(harness(f, DecisionDetailView(initialId: initialId)));
+      await tester.pumpWidget(harness(f, const DecisionDetailView()));
       await pumpAsync(tester);
+      if (initialId != null) await open(tester, initialId);
     }
 
     testWidgets('pin jump affordance not visible before pin set', (tester) async {
@@ -734,8 +748,7 @@ void main() {
       await pumpAsync(tester);
 
       // Navigate to D-2.
-      f.services.messages.publish('builtin.decisions', 'selection', {'id': 'D-2'});
-      await pumpAsync(tester);
+      await open(tester, 'D-2');
       // Title appears in pane header subtitle + body card.
       expect(find.text('Decision D-2'), findsWidgets);
 
@@ -762,8 +775,7 @@ void main() {
       await pumpAsync(tester);
 
       // Navigate to D-2.
-      f.services.messages.publish('builtin.decisions', 'selection', {'id': 'D-2'});
-      await pumpAsync(tester);
+      await open(tester, 'D-2');
 
       // Replace pin with D-2.
       await tester.tap(find
@@ -774,8 +786,7 @@ void main() {
       await pumpAsync(tester);
 
       // Navigate to D-3.
-      f.services.messages.publish('builtin.decisions', 'selection', {'id': 'D-3'});
-      await pumpAsync(tester);
+      await open(tester, 'D-3');
 
       // Jump to pin — should go to D-2 (replaced), not D-1.
       await tester.tap(find

test/builtin/editor/editor_extension_test.dart

@@ -0,0 +1,75 @@
+/// T-197: EditorExtension reveals its workspace tab when a buffer opens.
+///
+/// `editor.open` opens the buffer daemon-side and emits `editor.opened`,
+/// but nothing else brings the editor tab to front over the Claude
+/// pane. The extension's activate() listens for the editor lifecycle
+/// events and activates the workspace tab.
+library;
+
+import 'package:clide/builtin/editor/src/extension.dart';
+import 'package:clide/extension/extension.dart' show TabContribution;
+import 'package:clide/kernel/kernel.dart';
+import 'package:flutter/widgets.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+import '../../helpers/kernel_fixture.dart';
+
+void main() {
+  late KernelFixture f;
+
+  setUp(() async {
+    f = await KernelFixture.create();
+    f.services.panels.registerSlot(const SlotDefinition(id: Slots.workspace, position: SlotPosition.center));
+    // A pre-existing workspace tab so 'editor.active' is NOT the default
+    // active tab — the reveal must switch to it explicitly.
+    f.services.panels.contribute(TabContribution(
+      id: 'claude.primary',
+      slot: Slots.workspace,
+      title: 'Claude',
+      build: (_) => const SizedBox(),
+    ));
+    f.services.extensions.register(EditorExtension());
+    await f.services.extensions.activate('builtin.editor');
+  });
+  tearDown(() => f.dispose());
+
+  void emitEditor(String kind, {String? id}) {
+    f.services.events.emit(DaemonEvent(subsystem: 'editor', kind: kind, data: {'id': id}, ts: DateTime.now().toUtc()));
+  }
+
+  test('contributes editor.active but leaves Claude active by default', () {
+    expect(f.services.panels.tabsFor(Slots.workspace).any((t) => t.id == 'editor.active'), isTrue);
+    expect(f.services.panels.activeTabIn(Slots.workspace), 'claude.primary');
+  });
+
+  test('editor.opened reveals (activates) the editor tab', () async {
+    emitEditor('editor.opened', id: 'b_1');
+    await Future<void>.delayed(Duration.zero);
+    expect(f.services.panels.activeTabIn(Slots.workspace), 'editor.active');
+  });
+
+  test('editor.active-changed also reveals the editor tab', () async {
+    emitEditor('editor.active-changed', id: 'b_2');
+    await Future<void>.delayed(Duration.zero);
+    expect(f.services.panels.activeTabIn(Slots.workspace), 'editor.active');
+  });
+
+  test('a non-editor event leaves the active tab unchanged', () async {
+    f.services.events.emit(DaemonEvent(subsystem: 'git', kind: 'changed', data: const {}, ts: DateTime.now().toUtc()));
+    await Future<void>.delayed(Duration.zero);
+    expect(f.services.panels.activeTabIn(Slots.workspace), 'claude.primary');
+  });
+
+  test('an unrelated editor event kind does not reveal', () async {
+    emitEditor('editor.saved', id: 'b_1');
+    await Future<void>.delayed(Duration.zero);
+    expect(f.services.panels.activeTabIn(Slots.workspace), 'claude.primary');
+  });
+
+  test('after deactivate, editor events no longer reveal', () async {
+    await f.services.extensions.deactivate('builtin.editor');
+    emitEditor('editor.opened', id: 'b_9');
+    await Future<void>.delayed(Duration.zero);
+    expect(f.services.panels.activeTabIn(Slots.workspace), isNot('editor.active'));
+  });
+}

test/builtin/markdown/markdown_viewer_test.dart

@@ -50,9 +50,10 @@ Future<void> pumpView(WidgetTester tester, KernelFixture f) async {
   await pumpAsync(tester);
 }
 
-/// Trigger a file load via the 'load' channel (mirrors the extension bridge).
+/// Open a file through the retained nav (the history source); its 'load'
+/// emit makes the mounted viewer display it (T-196).
 Future<void> loadFile(WidgetTester tester, KernelFixture f, String path) async {
-  f.services.messages.publish('builtin.markdown', 'load', {'path': path});
+  f.services.readerNav.navFor('builtin.markdown', dataKey: 'path').open(path);
   await pumpAsync(tester);
 }
 

test/builtin/shared/reader_chrome_test.dart

@@ -1,222 +0,0 @@
-/// Unit tests for [ReaderHistory] and [ReaderHistoryMixin] (T-189, T-190).
-library;
-
-import 'package:clide/builtin/shared/reader_chrome.dart';
-import 'package:flutter/widgets.dart';
-import 'package:flutter_test/flutter_test.dart';
-
-// ---------------------------------------------------------------------------
-// ReaderHistory unit tests (no Flutter needed — plain test())
-// ---------------------------------------------------------------------------
-
-void main() {
-  group('ReaderHistory', () {
-    late ReaderHistory<String> h;
-
-    setUp(() => h = ReaderHistory<String>());
-
-    test('starts empty — canGoBack/Forward false, current null', () {
-      expect(h.canGoBack, isFalse);
-      expect(h.canGoForward, isFalse);
-      expect(h.current, isNull);
-    });
-
-    test('push one — current is that entry, no back/forward', () {
-      h.push('A');
-      expect(h.current, 'A');
-      expect(h.canGoBack, isFalse);
-      expect(h.canGoForward, isFalse);
-    });
-
-    test('push two — canGoBack true, canGoForward false', () {
-      h.push('A');
-      h.push('B');
-      expect(h.current, 'B');
-      expect(h.canGoBack, isTrue);
-      expect(h.canGoForward, isFalse);
-    });
-
-    test('back() after two pushes returns first entry', () {
-      h.push('A');
-      h.push('B');
-      final result = h.back();
-      expect(result, 'A');
-      expect(h.current, 'A');
-      expect(h.canGoBack, isFalse);
-      expect(h.canGoForward, isTrue);
-    });
-
-    test('forward() after back() returns second entry', () {
-      h.push('A');
-      h.push('B');
-      h.back();
-      final result = h.forward();
-      expect(result, 'B');
-      expect(h.current, 'B');
-      expect(h.canGoForward, isFalse);
-    });
-
-    test('back() at start returns null', () {
-      h.push('A');
-      expect(h.back(), isNull);
-    });
-
-    test('forward() at end returns null', () {
-      h.push('A');
-      h.push('B');
-      expect(h.forward(), isNull);
-    });
-
-    test('new push truncates forward history', () {
-      h.push('A');
-      h.push('B');
-      h.push('C');
-      h.back(); // now at B
-      h.back(); // now at A
-      expect(h.canGoForward, isTrue);
-
-      h.push('D'); // truncates [B, C], appends D
-      expect(h.current, 'D');
-      expect(h.canGoBack, isTrue);
-      expect(h.canGoForward, isFalse);
-
-      final prev = h.back();
-      expect(prev, 'A');
-    });
-
-    test('pushing duplicate of current is a no-op', () {
-      h.push('A');
-      h.push('A');
-      expect(h.canGoBack, isFalse); // still only one entry
-      expect(h.current, 'A');
-    });
-
-    test('three entries back/forward round-trip', () {
-      h.push('A');
-      h.push('B');
-      h.push('C');
-      expect(h.back(), 'B');
-      expect(h.back(), 'A');
-      expect(h.forward(), 'B');
-      expect(h.forward(), 'C');
-      expect(h.canGoForward, isFalse);
-    });
-  });
-
-  // -------------------------------------------------------------------------
-  // ReaderHistoryMixin widget integration test — uses a minimal StatefulWidget.
-  // -------------------------------------------------------------------------
-
-  group('ReaderHistoryMixin', () {
-    testWidgets('pin current / jump-to-pin round-trip', (tester) async {
-      String? jumpedTo;
-
-      await tester.pumpWidget(
-        Directionality(
-          textDirection: TextDirection.ltr,
-          child: _MixinHarness(onJump: (v) => jumpedTo = v),
-        ),
-      );
-
-      final state = tester.state<_MixinHarnessState>(find.byType(_MixinHarness));
-
-      // No pin yet.
-      expect(state.hasPinned, isFalse);
-      expect(state.pinnedEntry, isNull);
-
-      // Push 'A', then pin it.
-      state.historyPush('A');
-      await tester.pump();
-      state.pinCurrent();
-      await tester.pump();
-
-      expect(state.hasPinned, isTrue);
-      expect(state.pinnedEntry, 'A');
-
-      // Push 'B', jump to pin → should get 'A'.
-      state.historyPush('B');
-      await tester.pump();
-      final pinEntry = state.jumpToPin();
-      jumpedTo = pinEntry;
-      expect(jumpedTo, 'A');
-    });
-
-    testWidgets('pin replaces previous pin', (tester) async {
-      await tester.pumpWidget(
-        Directionality(
-          textDirection: TextDirection.ltr,
-          child: _MixinHarness(onJump: (_) {}),
-        ),
-      );
-
-      final state = tester.state<_MixinHarnessState>(find.byType(_MixinHarness));
-      state.historyPush('A');
-      state.pinCurrent();
-      await tester.pump();
-      expect(state.pinnedEntry, 'A');
-
-      state.historyPush('B');
-      state.pinCurrent();
-      await tester.pump();
-      expect(state.pinnedEntry, 'B'); // replaced
-    });
-
-    testWidgets('historyBack / historyForward returns correct entries', (tester) async {
-      await tester.pumpWidget(
-        Directionality(
-          textDirection: TextDirection.ltr,
-          child: _MixinHarness(onJump: (_) {}),
-        ),
-      );
-
-      final state = tester.state<_MixinHarnessState>(find.byType(_MixinHarness));
-      state.historyPush('X');
-      state.historyPush('Y');
-      await tester.pump();
-
-      expect(state.canGoBack, isTrue);
-      expect(state.canGoForward, isFalse);
-
-      final back = state.historyBack();
-      await tester.pump();
-      expect(back, 'X');
-      expect(state.canGoBack, isFalse);
-      expect(state.canGoForward, isTrue);
-
-      final fwd = state.historyForward();
-      await tester.pump();
-      expect(fwd, 'Y');
-    });
-
-    testWidgets('pinCurrent with empty history is a no-op', (tester) async {
-      await tester.pumpWidget(
-        Directionality(
-          textDirection: TextDirection.ltr,
-          child: _MixinHarness(onJump: (_) {}),
-        ),
-      );
-
-      final state = tester.state<_MixinHarnessState>(find.byType(_MixinHarness));
-      state.pinCurrent(); // no current entry — must not throw
-      await tester.pump();
-      expect(state.hasPinned, isFalse);
-    });
-  });
-}
-
-// ---------------------------------------------------------------------------
-// Minimal harness widget that mixes in ReaderHistoryMixin.
-// ---------------------------------------------------------------------------
-
-class _MixinHarness extends StatefulWidget {
-  const _MixinHarness({required this.onJump});
-  final void Function(String?) onJump;
-
-  @override
-  State<_MixinHarness> createState() => _MixinHarnessState();
-}
-
-class _MixinHarnessState extends State<_MixinHarness> with ReaderHistoryMixin<String, _MixinHarness> {
-  @override
-  Widget build(BuildContext context) => const SizedBox.shrink();
-}

test/kernel/reader_nav_test.dart

@@ -0,0 +1,137 @@
+/// Unit tests for the retained right-pane nav history (T-196).
+///
+/// [ReaderNav] records selections (even before the reader mounts), holds
+/// browser-style back/forward history, exposes the latest as [current]
+/// for grab-on-mount, and re-emits every navigation on the `load`
+/// channel so the reader has a single load path.
+library;
+
+import 'package:clide/kernel/src/events/message_bus.dart';
+import 'package:clide/kernel/src/reader_nav.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  late MessageBus bus;
+  late ReaderNav nav;
+  late List<String> loads;
+
+  setUp(() {
+    bus = MessageBus();
+    nav = ReaderNav(messages: bus, publisherId: 'builtin.decisions', dataKey: 'id');
+    loads = [];
+    bus.subscribe(publisher: 'builtin.decisions', channel: 'load').listen((m) {
+      final id = m.data['id'];
+      if (id is String) loads.add(id);
+    });
+  });
+  tearDown(() {
+    nav.dispose();
+    bus.dispose();
+  });
+
+  // Let the broadcast bus deliver.
+  Future<void> tick() => Future<void>.delayed(Duration.zero);
+
+  test('starts empty', () {
+    expect(nav.current, isNull);
+    expect(nav.canGoBack, isFalse);
+    expect(nav.canGoForward, isFalse);
+    expect(nav.hasPinned, isFalse);
+  });
+
+  test('open records the entry, sets current, and emits a load', () async {
+    nav.open('D-1');
+    expect(nav.current, 'D-1');
+    expect(nav.canGoBack, isFalse);
+    await tick();
+    expect(loads, ['D-1']);
+  });
+
+  test('a selection on the bus is recorded (retained) and emits a load', () async {
+    bus.publish('builtin.decisions', 'selection', {'id': 'D-9'});
+    await tick();
+    expect(nav.current, 'D-9');
+    expect(loads, ['D-9']);
+  });
+
+  test('two opens enable back; back re-emits the prior entry', () async {
+    nav.open('D-1');
+    nav.open('D-2');
+    expect(nav.canGoBack, isTrue);
+    expect(nav.canGoForward, isFalse);
+    nav.back();
+    expect(nav.current, 'D-1');
+    expect(nav.canGoForward, isTrue);
+    await tick();
+    expect(loads, ['D-1', 'D-2', 'D-1']);
+  });
+
+  test('forward after back re-emits the later entry', () async {
+    nav.open('D-1');
+    nav.open('D-2');
+    nav.back();
+    nav.forward();
+    expect(nav.current, 'D-2');
+  });
+
+  test('back at start / forward at end are no-ops', () async {
+    nav.open('D-1');
+    nav.back(); // canGoBack false → no-op
+    nav.forward(); // canGoForward false → no-op
+    await tick();
+    expect(loads, ['D-1']); // only the open emitted
+    expect(nav.current, 'D-1');
+  });
+
+  test('a new open truncates forward history', () {
+    nav.open('D-1');
+    nav.open('D-2');
+    nav.open('D-3');
+    nav.back(); // D-2
+    nav.back(); // D-1
+    nav.open('D-9'); // truncates D-2/D-3
+    expect(nav.current, 'D-9');
+    expect(nav.canGoForward, isFalse);
+    expect(nav.canGoBack, isTrue);
+  });
+
+  test('opening the current entry again re-emits but does not push', () async {
+    nav.open('D-1');
+    nav.open('D-1');
+    expect(nav.canGoBack, isFalse); // no duplicate pushed
+    await tick();
+    expect(loads, ['D-1', 'D-1']); // but both re-emit a load
+  });
+
+  test('pin + jumpToPin returns to the pinned entry and re-emits', () async {
+    nav.open('D-1');
+    nav.pin();
+    expect(nav.hasPinned, isTrue);
+    nav.open('D-2');
+    nav.open('D-3');
+    nav.jumpToPin();
+    expect(nav.current, 'D-1');
+    await tick();
+    expect(loads.last, 'D-1');
+  });
+
+  test('pin replaces the previous pin', () {
+    nav.open('D-1');
+    nav.pin();
+    nav.open('D-2');
+    nav.pin(); // replaces
+    nav.open('D-3');
+    nav.jumpToPin();
+    expect(nav.current, 'D-2');
+  });
+
+  test('registry retains one nav per reader id', () {
+    final reg = ReaderNavRegistry(bus);
+    addTearDown(reg.dispose);
+    final a = reg.navFor('builtin.markdown', dataKey: 'path');
+    final b = reg.navFor('builtin.markdown', dataKey: 'path');
+    expect(identical(a, b), isTrue);
+    final c = reg.navFor('builtin.decisions', dataKey: 'id');
+    expect(identical(a, c), isFalse);
+  });
+}