test: Add TestZulipApp; replace uses of ZulipApp

Greg noticed an instance where using ZulipApp directly was causing
tests to slow down by some 75%:
  #805 (comment)
Specifically, that was when we converted the emoji-reaction widget
tests over to use ZulipApp instead of mimicking it with a
MaterialApp, etc.

It's helpful to use something approaching the real ZulipApp. But
we'd like to avoid that slowdown, especially if it's happening in
code that most tests don't need to exercise. So, here's a
stripped-down version that does that. It takes roughly the same time
as the MaterialApp approach in those emoji-reaction tests. (11s on
my machine, vs. 16s with ZulipApp.)

This commit just converts the tests that were using ZulipApp. Next,
we'll sweep through and treat the ones using the ad hoc MaterialApp
approach.

Author: chrisbobbe

test/notifications/display_test.dart

@@ -340,6 +340,8 @@ void main() {
       pushedRoutes = [];
       final testNavObserver = TestNavigatorObserver()
         ..onPushed = (route, prevRoute) => pushedRoutes.add(route);
+      // This uses [ZulipApp] instead of [TestZulipApp] because notification
+      // logic uses `await ZulipApp.navigator`.
       await tester.pumpWidget(ZulipApp(navigatorObservers: [testNavObserver]));
       if (early) {
         check(pushedRoutes).isEmpty();

test/widgets/code_block_test.dart

@@ -1,11 +1,10 @@
 import 'package:checks/checks.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:zulip/widgets/app.dart';
 import 'package:zulip/widgets/code_block.dart';
-import 'package:zulip/widgets/page.dart';
 
 import '../model/binding.dart';
+import 'test_app.dart';
 
 void main() {
   TestZulipBinding.ensureInitialized();
@@ -14,12 +13,8 @@ void main() {
     group('lerp', () {
       Future<BuildContext> contextWithZulipTheme(WidgetTester tester) async {
         addTearDown(testBinding.reset);
-        await tester.pumpWidget(const ZulipApp());
+        await tester.pumpWidget(const TestZulipApp());
         await tester.pump();
-        final navigator = await ZulipApp.navigator;
-        navigator.push(MaterialWidgetRoute(page: Builder(
-          builder: (context) => const Placeholder())));
-        await tester.pumpAndSettle();
         return tester.element(find.byType(Placeholder));
       }
 

test/widgets/inbox_test.dart

@@ -4,7 +4,6 @@ import 'package:flutter_test/flutter_test.dart';
 import 'package:zulip/api/model/events.dart';
 import 'package:zulip/api/model/model.dart';
 import 'package:zulip/model/store.dart';
-import 'package:zulip/widgets/app.dart';
 import 'package:zulip/widgets/icons.dart';
 import 'package:zulip/widgets/inbox.dart';
 import 'package:zulip/widgets/stream_colors.dart';
@@ -13,6 +12,7 @@ import '../example_data.dart' as eg;
 import '../flutter_checks.dart';
 import '../model/binding.dart';
 import '../model/test_store.dart';
+import 'test_app.dart';
 
 /// Repeatedly drags `view` by `moveStep` until `finder` is invisible.
 ///
@@ -71,11 +71,12 @@ void main() {
       await store.handleEvent(MessageEvent(id: 1, message: message));
     }
 
-    await tester.pumpWidget(
-      ZulipApp(navigatorObservers: [if (navigatorObserver != null) navigatorObserver]));
+    await tester.pumpWidget(TestZulipApp(
+      accountId: eg.selfAccount.id,
+      navigatorObservers: [if (navigatorObserver != null) navigatorObserver],
+      child: const InboxPage(),
+    ));
     await tester.pump();
-    final navigator = await ZulipApp.navigator;
-    navigator.push(InboxPage.buildRoute(accountId: eg.selfAccount.id));
 
     // global store and per-account store get loaded
     await tester.pumpAndSettle();

test/widgets/test_app.dart

@@ -0,0 +1,44 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_gen/gen_l10n/zulip_localizations.dart';
+
+import 'package:zulip/widgets/store.dart';
+import 'package:zulip/widgets/theme.dart';
+
+/// A lightweight mock of [ZulipApp], suitable for most widget tests.
+class TestZulipApp extends StatelessWidget {
+  const TestZulipApp({
+    super.key,
+    this.accountId,
+    this.child = const Placeholder(),
+    this.navigatorObservers,
+  });
+
+  final int? accountId;
+
+  /// A [Widget] to render on the home page.
+  ///
+  /// If [accountId] is provided, this is wrapped in a [PerAccountStoreWidget].
+  ///
+  /// Defaults to `Placeholder()`.
+  final Widget child;
+
+  /// A list to pass through to [MaterialApp.navigatorObservers].
+  final List<NavigatorObserver>? navigatorObservers;
+
+  @override
+  Widget build(BuildContext context) {
+    return GlobalStoreWidget(
+      child: MaterialApp(
+        title: 'Zulip',
+        localizationsDelegates: ZulipLocalizations.localizationsDelegates,
+        supportedLocales: ZulipLocalizations.supportedLocales,
+        theme: zulipThemeData(context),
+
+        navigatorObservers: navigatorObservers ?? const [],
+
+        home: accountId != null
+          ? PerAccountStoreWidget(accountId: accountId!, child: child)
+          : child,
+      ));
+  }
+}

test/widgets/text_test.dart

@@ -2,12 +2,11 @@ import 'package:checks/checks.dart';
 import 'package:collection/collection.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:zulip/widgets/app.dart';
-import 'package:zulip/widgets/page.dart';
 import 'package:zulip/widgets/text.dart';
 
 import '../flutter_checks.dart';
 import '../model/binding.dart';
+import 'test_app.dart';
 
 // From trying the options on an iPhone 13 Pro running iOS 16.6.1:
 const kTextScaleFactors = <double>[
@@ -397,13 +396,9 @@ void main() {
         addTearDown(tester.platformDispatcher.clearLocaleTestValue);
         addTearDown(tester.platformDispatcher.clearLocalesTestValue);
 
-        await tester.pumpWidget(const ZulipApp());
-        await tester.pump();
-
-        final navigator = await ZulipApp.navigator;
-        navigator.push(MaterialWidgetRoute(page: Builder(builder: (context) =>
+        await tester.pumpWidget(TestZulipApp(child: Builder(builder: (context) =>
           Text('123', style: TextStyle(textBaseline: localizedTextBaseline(context))))));
-        await tester.pumpAndSettle();
+        await tester.pump();
 
         final TextStyle? style = tester.widget<Text>(find.text('123')).style;
         final actualTextBaseline = style!.textBaseline!;

test/widgets/theme_test.dart

@@ -2,15 +2,14 @@ import 'package:checks/checks.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:zulip/widgets/app.dart';
-import 'package:zulip/widgets/page.dart';
 import 'package:zulip/widgets/stream_colors.dart';
 import 'package:zulip/widgets/text.dart';
 import 'package:zulip/widgets/theme.dart';
 
 import '../example_data.dart' as eg;
 import '../flutter_checks.dart';
 import '../model/binding.dart';
+import 'test_app.dart';
 
 void main() {
   TestZulipBinding.ensureInitialized();
@@ -118,14 +117,9 @@ void main() {
       tester.platformDispatcher.platformBrightnessTestValue = Brightness.light;
       addTearDown(tester.platformDispatcher.clearPlatformBrightnessTestValue);
 
-      await tester.pumpWidget(const ZulipApp());
+      await tester.pumpWidget(const TestZulipApp());
       await tester.pump();
 
-      final navigator = await ZulipApp.navigator;
-      navigator.push(MaterialWidgetRoute(page: Builder(builder: (context) =>
-        const Placeholder())));
-      await tester.pumpAndSettle();
-
       final element = tester.element(find.byType(Placeholder));
       // Compares all the swatch's members; see [ColorSwatch]'s `operator ==`.
       check(colorSwatchFor(element, subscription))