test(T2): add widget tests for ThreadDetailScreen and SearchScreen

Six tests for ThreadDetailScreen:
- empty thread shows placeholder message
- sender name rendered in card
- last email is expanded by default (reply/delete buttons visible)
- tapping expanded card collapses it
- flagged email shows star icon
- expanded card renders plain text body

Six tests for SearchScreen:
- placeholder shown when field is empty
- typing fewer than 3 characters keeps placeholder (no search fires)
- search returning empty shows "No results"
- email results shown under "Messages" section
- folder results shown under "Folders" section
- clear button resets results to placeholder

Also adds ThreadDetailScreen route to the shared test router in
helpers.dart so tests can navigate to it by URL.

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

test/widget/helpers.dart

@@ -30,6 +30,7 @@ import 'package:sharedinbox/ui/screens/email_detail_screen.dart';
 import 'package:sharedinbox/ui/screens/email_list_screen.dart';
 import 'package:sharedinbox/ui/screens/mailbox_list_screen.dart';
 import 'package:sharedinbox/ui/screens/search_screen.dart';
+import 'package:sharedinbox/ui/screens/thread_detail_screen.dart';
 
 // ---------------------------------------------------------------------------
 // Fake repositories
@@ -381,6 +382,18 @@ Widget buildApp({
                   ),
                 ],
               ),
+              GoRoute(
+                path: ':mailboxPath/threads/:threadId',
+                builder: (ctx, state) => ThreadDetailScreen(
+                  accountId: state.pathParameters['accountId']!,
+                  mailboxPath: Uri.decodeComponent(
+                    state.pathParameters['mailboxPath']!,
+                  ),
+                  threadId: Uri.decodeComponent(
+                    state.pathParameters['threadId']!,
+                  ),
+                ),
+              ),
             ],
           ),
         ],

test/widget/search_screen_test.dart

@@ -0,0 +1,182 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+import 'package:sharedinbox/core/models/mailbox.dart';
+import 'package:sharedinbox/di.dart';
+
+import 'helpers.dart';
+
+void main() {
+  group('SearchScreen', () {
+    testWidgets('shows placeholder hint text when empty', (tester) async {
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/search',
+          overrides: [
+            accountRepositoryProvider.overrideWithValue(
+              FakeAccountRepository([kTestAccount]),
+            ),
+            mailboxRepositoryProvider.overrideWithValue(
+              FakeMailboxRepository(),
+            ),
+            emailRepositoryProvider.overrideWithValue(FakeEmailRepository()),
+          ],
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      expect(find.text('Type 3+ characters to search'), findsOneWidget);
+    });
+
+    testWidgets('typing fewer than 3 characters does not trigger search', (
+      tester,
+    ) async {
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/search',
+          overrides: [
+            accountRepositoryProvider.overrideWithValue(
+              FakeAccountRepository([kTestAccount]),
+            ),
+            mailboxRepositoryProvider.overrideWithValue(
+              FakeMailboxRepository(),
+            ),
+            emailRepositoryProvider.overrideWithValue(FakeEmailRepository()),
+          ],
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      await tester.enterText(find.byType(TextField), 'hi');
+      await tester.pump(const Duration(milliseconds: 400));
+
+      expect(find.text('Type 3+ characters to search'), findsOneWidget);
+      expect(find.text('No results'), findsNothing);
+    });
+
+    testWidgets('shows "No results" when search returns nothing', (
+      tester,
+    ) async {
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/search',
+          overrides: [
+            accountRepositoryProvider.overrideWithValue(
+              FakeAccountRepository([kTestAccount]),
+            ),
+            mailboxRepositoryProvider.overrideWithValue(
+              FakeMailboxRepository(),
+            ),
+            emailRepositoryProvider.overrideWithValue(FakeEmailRepository()),
+          ],
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      await tester.enterText(find.byType(TextField), 'xyz');
+      await tester.pump(const Duration(milliseconds: 400));
+      await tester.pumpAndSettle();
+
+      expect(find.text('No results'), findsOneWidget);
+    });
+
+    testWidgets('shows email results under "Messages" section', (
+      tester,
+    ) async {
+      final email = testEmail(subject: 'Invoice Q3');
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/search',
+          overrides: [
+            accountRepositoryProvider.overrideWithValue(
+              FakeAccountRepository([kTestAccount]),
+            ),
+            mailboxRepositoryProvider.overrideWithValue(
+              FakeMailboxRepository(),
+            ),
+            emailRepositoryProvider.overrideWithValue(
+              FakeEmailRepository(searchResults: [email]),
+            ),
+          ],
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      await tester.enterText(find.byType(TextField), 'inv');
+      await tester.pump(const Duration(milliseconds: 400));
+      await tester.pumpAndSettle();
+
+      expect(find.text('Messages'), findsOneWidget);
+      expect(find.text('Invoice Q3'), findsOneWidget);
+    });
+
+    testWidgets('shows folder results under "Folders" section', (
+      tester,
+    ) async {
+      const archiveMailbox = Mailbox(
+        id: 'acc-1:Archive',
+        accountId: 'acc-1',
+        path: 'Archive',
+        name: 'Archive',
+        unreadCount: 0,
+        totalCount: 5,
+      );
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/search',
+          overrides: [
+            accountRepositoryProvider.overrideWithValue(
+              FakeAccountRepository([kTestAccount]),
+            ),
+            mailboxRepositoryProvider.overrideWithValue(
+              FakeMailboxRepository([archiveMailbox]),
+            ),
+            emailRepositoryProvider.overrideWithValue(FakeEmailRepository()),
+          ],
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      await tester.enterText(find.byType(TextField), 'arc');
+      await tester.pump(const Duration(milliseconds: 400));
+      await tester.pumpAndSettle();
+
+      expect(find.text('Folders'), findsOneWidget);
+      expect(find.text('Archive'), findsOneWidget);
+    });
+
+    testWidgets('tapping clear button resets results to placeholder', (
+      tester,
+    ) async {
+      final email = testEmail(subject: 'Found email');
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/search',
+          overrides: [
+            accountRepositoryProvider.overrideWithValue(
+              FakeAccountRepository([kTestAccount]),
+            ),
+            mailboxRepositoryProvider.overrideWithValue(
+              FakeMailboxRepository(),
+            ),
+            emailRepositoryProvider.overrideWithValue(
+              FakeEmailRepository(searchResults: [email]),
+            ),
+          ],
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      await tester.enterText(find.byType(TextField), 'found');
+      await tester.pump(const Duration(milliseconds: 400));
+      await tester.pumpAndSettle();
+      expect(find.text('Found email'), findsOneWidget);
+
+      await tester.tap(find.byIcon(Icons.clear));
+      await tester.pumpAndSettle();
+
+      expect(find.text('Found email'), findsNothing);
+      expect(find.text('Type 3+ characters to search'), findsOneWidget);
+    });
+  });
+}

test/widget/thread_detail_screen_test.dart

@@ -0,0 +1,198 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+import 'package:sharedinbox/core/models/email.dart';
+import 'package:sharedinbox/di.dart';
+
+import 'helpers.dart';
+
+Email _threadEmail({
+  String id = 'acc-1:10',
+  bool isFlagged = false,
+  bool isSeen = true,
+}) =>
+    Email(
+      id: id,
+      accountId: 'acc-1',
+      mailboxPath: 'INBOX',
+      uid: 10,
+      threadId: 'thread-1',
+      subject: 'Project update',
+      receivedAt: DateTime(2024, 6),
+      sentAt: DateTime(2024, 6, 1, 9),
+      from: const [EmailAddress(name: 'Bob', email: 'bob@example.com')],
+      to: const [EmailAddress(email: 'alice@example.com')],
+      cc: const [],
+      isSeen: isSeen,
+      isFlagged: isFlagged,
+      hasAttachment: false,
+    );
+
+void main() {
+  group('ThreadDetailScreen', () {
+    testWidgets('shows "Thread not found or empty" when thread is empty', (
+      tester,
+    ) async {
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/mailboxes/INBOX/threads/thread-1',
+          overrides: [
+            accountRepositoryProvider.overrideWithValue(
+              FakeAccountRepository([kTestAccount]),
+            ),
+            mailboxRepositoryProvider.overrideWithValue(
+              FakeMailboxRepository(),
+            ),
+            emailRepositoryProvider.overrideWithValue(FakeEmailRepository()),
+          ],
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      expect(find.text('Thread not found or empty'), findsOneWidget);
+    });
+
+    testWidgets('shows sender name for email in thread', (tester) async {
+      final email = _threadEmail();
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/mailboxes/INBOX/threads/thread-1',
+          overrides: [
+            accountRepositoryProvider.overrideWithValue(
+              FakeAccountRepository([kTestAccount]),
+            ),
+            mailboxRepositoryProvider.overrideWithValue(
+              FakeMailboxRepository(),
+            ),
+            emailRepositoryProvider.overrideWithValue(
+              FakeEmailRepository(emails: [email]),
+            ),
+          ],
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      expect(find.textContaining('Bob'), findsOneWidget);
+    });
+
+    testWidgets('last email in thread is expanded by default', (tester) async {
+      final email = _threadEmail();
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/mailboxes/INBOX/threads/thread-1',
+          overrides: [
+            accountRepositoryProvider.overrideWithValue(
+              FakeAccountRepository([kTestAccount]),
+            ),
+            mailboxRepositoryProvider.overrideWithValue(
+              FakeMailboxRepository(),
+            ),
+            emailRepositoryProvider.overrideWithValue(
+              FakeEmailRepository(
+                emails: [email],
+                emailBody: const EmailBody(
+                  emailId: 'acc-1:10',
+                  textBody: 'Hello body text',
+                  attachments: [],
+                ),
+              ),
+            ),
+          ],
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      // Reply and delete buttons are visible for the expanded card.
+      expect(find.byIcon(Icons.reply), findsOneWidget);
+      expect(find.byIcon(Icons.delete_outline), findsOneWidget);
+    });
+
+    testWidgets('tapping an expanded card collapses it', (tester) async {
+      final email = _threadEmail();
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/mailboxes/INBOX/threads/thread-1',
+          overrides: [
+            accountRepositoryProvider.overrideWithValue(
+              FakeAccountRepository([kTestAccount]),
+            ),
+            mailboxRepositoryProvider.overrideWithValue(
+              FakeMailboxRepository(),
+            ),
+            emailRepositoryProvider.overrideWithValue(
+              FakeEmailRepository(
+                emails: [email],
+                emailBody: const EmailBody(
+                  emailId: 'acc-1:10',
+                  textBody: 'Hello body text',
+                  attachments: [],
+                ),
+              ),
+            ),
+          ],
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      // Tap the expand_less icon to collapse.
+      await tester.tap(find.byIcon(Icons.expand_less));
+      await tester.pumpAndSettle();
+
+      expect(find.byIcon(Icons.reply), findsNothing);
+      expect(find.byIcon(Icons.expand_more), findsOneWidget);
+    });
+
+    testWidgets('flagged email shows star icon', (tester) async {
+      final email = _threadEmail(isFlagged: true);
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/mailboxes/INBOX/threads/thread-1',
+          overrides: [
+            accountRepositoryProvider.overrideWithValue(
+              FakeAccountRepository([kTestAccount]),
+            ),
+            mailboxRepositoryProvider.overrideWithValue(
+              FakeMailboxRepository(),
+            ),
+            emailRepositoryProvider.overrideWithValue(
+              FakeEmailRepository(emails: [email]),
+            ),
+          ],
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      expect(find.byIcon(Icons.star), findsOneWidget);
+    });
+
+    testWidgets('expanded card shows plain text body', (tester) async {
+      final email = _threadEmail();
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/mailboxes/INBOX/threads/thread-1',
+          overrides: [
+            accountRepositoryProvider.overrideWithValue(
+              FakeAccountRepository([kTestAccount]),
+            ),
+            mailboxRepositoryProvider.overrideWithValue(
+              FakeMailboxRepository(),
+            ),
+            emailRepositoryProvider.overrideWithValue(
+              FakeEmailRepository(
+                emails: [email],
+                emailBody: const EmailBody(
+                  emailId: 'acc-1:10',
+                  textBody: 'Body content here',
+                  attachments: [],
+                ),
+              ),
+            ),
+          ],
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      expect(find.text('Body content here'), findsOneWidget);
+    });
+  });
+}