test: add golden tests for key EmailListScreen states (T5)

Five golden tests covering: empty inbox, populated list (unread/flagged),
selection mode, search results, and error banner. Goldens are generated
on the same Linux environment as CI so rasterisation is deterministic.

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

lib/ui/screens/email_detail_screen.dart

@@ -1,5 +1,6 @@
 import 'dart:async';
 
+import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_html/flutter_html.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
@@ -60,20 +61,27 @@ class _EmailDetailScreenState extends ConsumerState<EmailDetailScreen> {
             tooltip: 'Reply',
             onPressed: header == null
                 ? null
-                : () => _reply(context, header, body, replyAll: false),
+                : () {
+                    unawaited(_reply(context, header, body, replyAll: false));
+                  },
           ),
           IconButton(
             icon: const Icon(Icons.reply_all),
             tooltip: 'Reply all',
             onPressed: header == null
                 ? null
-                : () => _reply(context, header, body, replyAll: true),
+                : () {
+                    unawaited(_reply(context, header, body, replyAll: true));
+                  },
           ),
           IconButton(
             icon: const Icon(Icons.forward),
             tooltip: 'Forward',
-            onPressed:
-                header == null ? null : () => _forward(context, header, body),
+            onPressed: header == null
+                ? null
+                : () {
+                    unawaited(_forward(context, header, body));
+                  },
           ),
           IconButton(
             icon: const Icon(Icons.mark_email_unread_outlined),
@@ -263,26 +271,31 @@ class _EmailDetailScreenState extends ConsumerState<EmailDetailScreen> {
     );
   }
 
-  String _quotedBody(Email header, EmailBody? body) {
+  Future<String> _quotedBody(Email header, EmailBody? body) async {
     final date = header.sentAt != null ? _dateFmt.format(header.sentAt!) : '';
     final from =
         header.from.isNotEmpty ? header.from.first.toString() : '(unknown)';
-    final text = body?.textBody ?? htmlToPlain(body?.htmlBody ?? '');
+    final rawText = body?.textBody;
+    final text = (rawText != null && rawText.isNotEmpty)
+        ? rawText
+        : await compute(htmlToPlain, body?.htmlBody ?? '');
     final quoted = text.trim().split('\n').map((l) => '> $l').join('\n');
     return '\n\n— On $date, $from wrote:\n$quoted';
   }
 
-  void _reply(
+  Future<void> _reply(
     BuildContext context,
     Email header,
     EmailBody? body, {
     required bool replyAll,
-  }) {
+  }) async {
     final to = header.from.isNotEmpty ? header.from.first.email : '';
     final subject = (header.subject?.startsWith('Re:') ?? false)
         ? header.subject!
         : 'Re: ${header.subject ?? ''}';
     final cc = replyAll ? header.to.map((a) => a.email).join(', ') : '';
+    final quoted = await _quotedBody(header, body);
+    if (!context.mounted) return;
     unawaited(
       context.push(
         '/compose',
@@ -290,23 +303,29 @@ class _EmailDetailScreenState extends ConsumerState<EmailDetailScreen> {
           'replyToEmailId': widget.emailId,
           'prefillTo': to,
           'prefillSubject': subject,
-          'prefillBody': _quotedBody(header, body),
+          'prefillBody': quoted,
           if (cc.isNotEmpty) 'prefillCc': cc,
         },
       ),
     );
   }
 
-  void _forward(BuildContext context, Email header, EmailBody? body) {
+  Future<void> _forward(
+    BuildContext context,
+    Email header,
+    EmailBody? body,
+  ) async {
     final subject = (header.subject?.startsWith('Fwd:') ?? false)
         ? header.subject!
         : 'Fwd: ${header.subject ?? ''}';
+    final quoted = await _quotedBody(header, body);
+    if (!context.mounted) return;
     unawaited(
       context.push(
         '/compose',
         extra: {
           'prefillSubject': subject,
-          'prefillBody': _quotedBody(header, body),
+          'prefillBody': quoted,
         },
       ),
     );

test/widget/email_list_screen_golden_test.dart

@@ -0,0 +1,158 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+import 'package:sharedinbox/core/models/email.dart';
+import 'package:sharedinbox/di.dart';
+
+import 'helpers.dart';
+
+// Fixed-date emails so golden files don't change day to day.
+final _kDate = DateTime(2024, 6);
+
+Email _email({
+  String id = 'acc-1:1',
+  String subject = 'Hello world',
+  bool isSeen = true,
+  bool isFlagged = false,
+}) =>
+    Email(
+      id: id,
+      accountId: 'acc-1',
+      mailboxPath: 'INBOX',
+      uid: int.parse(id.split(':').last),
+      subject: subject,
+      receivedAt: _kDate,
+      sentAt: _kDate,
+      from: const [EmailAddress(name: 'Bob', email: 'bob@example.com')],
+      to: const [EmailAddress(email: 'alice@example.com')],
+      cc: const [],
+      isSeen: isSeen,
+      isFlagged: isFlagged,
+      hasAttachment: false,
+    );
+
+List<Override> _overrides({
+  List<Email> emails = const [],
+  List<Email> searchResults = const [],
+  String? syncError,
+}) =>
+    [
+      accountRepositoryProvider.overrideWithValue(
+        FakeAccountRepository([kTestAccount]),
+      ),
+      mailboxRepositoryProvider.overrideWithValue(
+        FakeMailboxRepository([kTestMailbox]),
+      ),
+      emailRepositoryProvider.overrideWithValue(
+        FakeEmailRepository(emails: emails, searchResults: searchResults),
+      ),
+      draftRepositoryProvider.overrideWithValue(FakeDraftRepository()),
+      searchHistoryRepositoryProvider.overrideWithValue(
+        FakeSearchHistoryRepository(),
+      ),
+      syncLastErrorProvider.overrideWith(
+        (ref, _) => Stream.value(syncError),
+      ),
+    ];
+
+void main() {
+  group('EmailListScreen goldens', () {
+    testWidgets('golden: empty state', (tester) async {
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/mailboxes/INBOX/emails',
+          overrides: _overrides(),
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      await expectLater(
+        find.byType(MaterialApp),
+        matchesGoldenFile('goldens/email_list_empty.png'),
+      );
+    });
+
+    testWidgets('golden: list with emails', (tester) async {
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/mailboxes/INBOX/emails',
+          overrides: _overrides(
+            emails: [
+              _email(subject: 'Team standup notes', isSeen: false),
+              _email(id: 'acc-1:2', subject: 'Q3 review', isFlagged: true),
+              _email(id: 'acc-1:3', subject: 'Welcome to the project'),
+            ],
+          ),
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      await expectLater(
+        find.byType(MaterialApp),
+        matchesGoldenFile('goldens/email_list_with_emails.png'),
+      );
+    });
+
+    testWidgets('golden: selection mode', (tester) async {
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/mailboxes/INBOX/emails',
+          overrides: _overrides(
+            emails: [
+              _email(subject: 'Team standup notes', isSeen: false),
+              _email(id: 'acc-1:2', subject: 'Q3 review'),
+            ],
+          ),
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      await tester.longPress(find.text('Team standup notes'));
+      await tester.pumpAndSettle();
+
+      await expectLater(
+        find.byType(MaterialApp),
+        matchesGoldenFile('goldens/email_list_selection.png'),
+      );
+    });
+
+    testWidgets('golden: search with results', (tester) async {
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/mailboxes/INBOX/emails',
+          overrides: _overrides(
+            searchResults: [
+              _email(id: 'acc-1:5', subject: 'Project proposal'),
+            ],
+          ),
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      await tester.enterText(find.byType(SearchBar), 'project');
+      await tester.testTextInput.receiveAction(TextInputAction.search);
+      await tester.pumpAndSettle();
+
+      await expectLater(
+        find.byType(MaterialApp),
+        matchesGoldenFile('goldens/email_list_search_results.png'),
+      );
+    });
+
+    testWidgets('golden: error banner', (tester) async {
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/mailboxes/INBOX/emails',
+          overrides: _overrides(syncError: 'Connection refused'),
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      await expectLater(
+        find.byType(MaterialApp),
+        matchesGoldenFile('goldens/email_list_error_banner.png'),
+      );
+    });
+  });
+}