Reland Add test for dynamic_content_color.0.dart (#158547)

Fixes https://github.com/flutter/flutter/issues/130459

Follow up of the reverted https://github.com/flutter/flutter/pull/158309

It adds a test for
- `examples/api/lib/material/color_scheme/dynamic_content_color.0.dart`

dev/bots/check_code_samples.dart

@@ -142,29 +142,18 @@ class SampleChecker {
     // Get a list of the filenames that were not found in the source files.
     final List<String> missingFilenames = checkForMissingLinks(exampleFilenames, exampleLinks);
 
-    // Get a list of any tests that are missing, as well as any that used to be
+    // Get a list of any tests that are missing.
-    // missing, but have been implemented.
+    final List<File> missingTests = checkForMissingTests(exampleFilenames);
-    final (List<File> missingTests, List<File> noLongerMissing) = checkForMissingTests(exampleFilenames);
 
     // Remove any that we know are exceptions (examples that aren't expected to be
     // linked into any source files). These are typically template files used to
     // generate new examples.
     missingFilenames.removeWhere((String file) => _knownUnlinkedExamples.contains(file));
 
-    if (missingFilenames.isEmpty && missingTests.isEmpty && noLongerMissing.isEmpty && malformedLinks.isEmpty) {
+    if (missingFilenames.isEmpty && missingTests.isEmpty && malformedLinks.isEmpty) {
       return true;
     }
 
-    if (noLongerMissing.isNotEmpty) {
-      final StringBuffer buffer = StringBuffer('The following tests have been implemented! Huzzah!:\n');
-      for (final File name in noLongerMissing) {
-        buffer.writeln('  ${getRelativePath(name)}');
-      }
-      buffer.writeln('However, they now need to be removed from the _knownMissingTests');
-      buffer.write('list in the script $_scriptLocation.');
-      foundError(buffer.toString().split('\n'));
-    }
-
     if (missingTests.isNotEmpty) {
       final StringBuffer buffer = StringBuffer('The following example test files are missing:\n');
       for (final File name in missingTests) {
@@ -279,35 +268,14 @@ class SampleChecker {
     return '${path.join(testPath, path.basenameWithoutExtension(example.path))}_test.dart';
   }
 
-  (List<File>, List<File>) checkForMissingTests(List<File> exampleFilenames) {
+  List<File> checkForMissingTests(List<File> exampleFilenames) {
     final List<File> missingTests = <File>[];
-    final List<File> noLongerMissingTests = <File>[];
     for (final File example in exampleFilenames) {
       final File testFile = filesystem.file(getTestNameForExample(example, examples));
-      final String name = path.relative(testFile.absolute.path, from: flutterRoot.absolute.path);
       if (!testFile.existsSync()) {
         missingTests.add(testFile);
-      } else if (_knownMissingTests.contains(name.replaceAll(r'\', '/'))) {
-        noLongerMissingTests.add(testFile);
       }
     }
-    // Skip any that we know are missing.
+    return missingTests;
-    missingTests.removeWhere(
-      (File test) {
-        final String name = path.relative(test.absolute.path, from: flutterRoot.absolute.path).replaceAll(r'\', '/');
-        return _knownMissingTests.contains(name);
-      },
-    );
-    return (missingTests, noLongerMissingTests);
   }
 }
-
-// These tests are known to be missing. They should all eventually be
-// implemented, but until they are we allow them, so that we can catch any new
-// examples that are added without tests.
-//
-// TODO(gspencergoog): implement the missing tests.
-// See https://github.com/flutter/flutter/issues/130459
-final Set<String> _knownMissingTests = <String>{
-  'examples/api/test/material/color_scheme/dynamic_content_color.0_test.dart',
-};

examples/api/lib/material/color_scheme/dynamic_content_color.0.dart

@@ -9,26 +9,34 @@ import 'package:flutter/material.dart';
 const Widget divider = SizedBox(height: 10);
 const double narrowScreenWidthThreshold = 400;
 
-void main() => runApp(DynamicColorExample());
+void main() => runApp(const DynamicColorExample());
 
 class DynamicColorExample extends StatefulWidget {
-  DynamicColorExample({super.key});
+  const DynamicColorExample({
+    this.loadColorScheme,
+    super.key,
+  });
 
-  final List<ImageProvider> images = <NetworkImage>[
+  static const List<ImageProvider> images = <NetworkImage>[
-    const NetworkImage(
+    NetworkImage(
         'https://flutter.github.io/assets-for-api-docs/assets/material/content_based_color_scheme_1.png'),
-    const NetworkImage(
+    NetworkImage(
         'https://flutter.github.io/assets-for-api-docs/assets/material/content_based_color_scheme_2.png'),
-    const NetworkImage(
+    NetworkImage(
         'https://flutter.github.io/assets-for-api-docs/assets/material/content_based_color_scheme_3.png'),
-    const NetworkImage(
+    NetworkImage(
         'https://flutter.github.io/assets-for-api-docs/assets/material/content_based_color_scheme_4.png'),
-    const NetworkImage(
+    NetworkImage(
         'https://flutter.github.io/assets-for-api-docs/assets/material/content_based_color_scheme_5.png'),
-    const NetworkImage(
+    NetworkImage(
         'https://flutter.github.io/assets-for-api-docs/assets/material/content_based_color_scheme_6.png'),
   ];
 
+  final Future<ColorScheme> Function(
+    ImageProvider<Object> provider,
+    Brightness brightness,
+  )? loadColorScheme;
+
   @override
   State<DynamicColorExample> createState() => _DynamicColorExampleState();
 }
@@ -48,7 +56,7 @@ class _DynamicColorExampleState extends State<DynamicColorExample> {
     isLoading = true;
     currentColorScheme = const ColorScheme.light();
     WidgetsBinding.instance.addPostFrameCallback((_) {
-      _updateImage(widget.images[selectedImage]);
+      _updateImage(DynamicColorExample.images[selectedImage]);
       isLoading = false;
     });
   }
@@ -105,7 +113,7 @@ class _DynamicColorExampleState extends State<DynamicColorExample> {
                   onChanged: (bool value) {
                     setState(() {
                       isLight = value;
-                      _updateImage(widget.images[selectedImage]);
+                      _updateImage(DynamicColorExample.images[selectedImage]);
                     });
                   })
             ],
@@ -120,7 +128,7 @@ class _DynamicColorExampleState extends State<DynamicColorExample> {
                         divider,
                         _imagesRow(
                           context,
-                          widget.images,
+                          DynamicColorExample.images,
                           colorScheme,
                         ),
                         divider,
@@ -186,13 +194,23 @@ class _DynamicColorExampleState extends State<DynamicColorExample> {
   }
 
   Future<void> _updateImage(ImageProvider provider) async {
-    final ColorScheme newColorScheme = await ColorScheme.fromImageProvider(
+    final ColorScheme newColorScheme;
-        provider: provider, brightness: isLight ? Brightness.light : Brightness.dark);
+    if (widget.loadColorScheme != null) {
+      newColorScheme = await widget.loadColorScheme!(
+        provider,
+        isLight ? Brightness.light : Brightness.dark,
+      );
+    } else {
+      newColorScheme = await ColorScheme.fromImageProvider(
+        provider: provider,
+        brightness: isLight ? Brightness.light : Brightness.dark,
+      );
+    }
     if (!mounted) {
       return;
     }
     setState(() {
-      selectedImage = widget.images.indexOf(provider);
+      selectedImage = DynamicColorExample.images.indexOf(provider);
       currentColorScheme = newColorScheme;
     });
   }
@@ -227,7 +245,7 @@ class _DynamicColorExampleState extends State<DynamicColorExample> {
               child: GestureDetector(
                 onTap: () => _updateImage(image),
                 child: Card(
-                  color: widget.images.indexOf(image) == selectedImage
+                  color: DynamicColorExample.images.indexOf(image) == selectedImage
                       ? colorScheme.primaryContainer
                       : colorScheme.surface,
                   child: Padding(

examples/api/test/material/color_scheme/dynamic_content_color.0_test.dart

@@ -0,0 +1,181 @@
+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:io';
+import 'dart:math';
+
+import 'package:flutter/material.dart';
+import 'package:flutter_api_samples/material/color_scheme/dynamic_content_color.0.dart' as example;
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  final List<(ImageProvider<Object>, Brightness)> loadColorSchemeCalls = <(ImageProvider<Object>, Brightness)>[];
+
+  Future<ColorScheme> fakeColorSchemeLoader(ImageProvider<Object> provider, Brightness brightness) async {
+    loadColorSchemeCalls.add((provider, brightness));
+    final int index = example.DynamicColorExample.images.indexOf(provider);
+    final int seedColor = 0xf * pow(0x10, index).toInt();
+    return ColorScheme.fromSeed(seedColor: Color(seedColor), brightness: brightness);
+  }
+
+  setUp(() {
+    loadColorSchemeCalls.clear();
+  });
+
+  // The app being tested loads images via HTTP which the test
+  // framework defeats by default.
+  setUpAll(() {
+    HttpOverrides.global = null;
+  });
+
+  testWidgets('The content is visible', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      example.DynamicColorExample(
+        loadColorScheme: fakeColorSchemeLoader,
+      ),
+    );
+    await tester.pump();
+
+    expect(
+      find.widgetWithText(AppBar, 'Content Based Dynamic Color'),
+      findsOne,
+    );
+    expect(find.byType(Switch), findsOne);
+    expect(find.byIcon(Icons.light_mode), findsOne);
+
+    expect(find.text('Light ColorScheme'), findsOne);
+    expect(find.text('Dark ColorScheme'), findsOne);
+    expect(find.text('primary'), findsExactly(2));
+    expect(find.text('onPrimary'), findsExactly(2));
+    expect(find.text('primaryContainer'), findsExactly(2));
+    expect(find.text('onPrimaryContainer'), findsExactly(2));
+    expect(find.text('secondary'), findsExactly(2));
+    expect(find.text('onSecondary'), findsExactly(2));
+    expect(find.text('secondaryContainer'), findsExactly(2));
+    expect(find.text('onSecondaryContainer'), findsExactly(2));
+    expect(find.text('tertiary'), findsExactly(2));
+    expect(find.text('onTertiary'), findsExactly(2));
+    expect(find.text('tertiaryContainer'), findsExactly(2));
+    expect(find.text('onTertiaryContainer'), findsExactly(2));
+    expect(find.text('error'), findsExactly(2));
+    expect(find.text('onError'), findsExactly(2));
+    expect(find.text('errorContainer'), findsExactly(2));
+    expect(find.text('onErrorContainer'), findsExactly(2));
+    expect(find.text('surface'), findsExactly(2));
+    expect(find.text('onSurface'), findsExactly(2));
+    expect(find.text('onSurfaceVariant'), findsExactly(2));
+    expect(find.text('outline'), findsExactly(2));
+    expect(find.text('shadow'), findsExactly(2));
+    expect(find.text('inverseSurface'), findsExactly(2));
+    expect(find.text('onInverseSurface'), findsExactly(2));
+    expect(find.text('inversePrimary'), findsExactly(2));
+
+    expect(loadColorSchemeCalls, hasLength(1));
+    expect(
+      loadColorSchemeCalls.single.$1,
+      isA<NetworkImage>()
+        .having(
+          (NetworkImage provider) => provider.url,
+          'url',
+          'https://flutter.github.io/assets-for-api-docs/assets/material/content_based_color_scheme_1.png',
+        ),
+    );
+    expect(
+      loadColorSchemeCalls.single.$2,
+      Brightness.light,
+    );
+
+    await tester.pumpAndSettle(); // Clears the timers from image loading.
+  });
+
+  testWidgets('The brightness can be changed', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      example.DynamicColorExample(
+        loadColorScheme: fakeColorSchemeLoader,
+      ),
+    );
+    await tester.pump();
+
+    expect(loadColorSchemeCalls, hasLength(1));
+    expect(
+      loadColorSchemeCalls.single.$1,
+      isA<NetworkImage>()
+        .having(
+          (NetworkImage provider) => provider.url,
+          'url',
+          'https://flutter.github.io/assets-for-api-docs/assets/material/content_based_color_scheme_1.png',
+        ),
+    );
+    expect(
+      loadColorSchemeCalls.single.$2,
+      Brightness.light,
+    );
+    await tester.pump();
+    await tester.pump(kThemeChangeDuration);
+
+    ThemeData themeData = Theme.of(tester.element(find.byType(Scaffold)));
+
+    expect(themeData.colorScheme.primary, const Color(0xff565992));
+    expect(themeData.colorScheme.secondary, const Color(0xff5c5d72));
+
+    await tester.tap(find.byType(Switch));
+    await tester.pump();
+
+    expect(loadColorSchemeCalls, hasLength(2));
+    expect(
+      loadColorSchemeCalls.last.$1,
+      isA<NetworkImage>()
+        .having(
+          (NetworkImage provider) => provider.url,
+          'url',
+          'https://flutter.github.io/assets-for-api-docs/assets/material/content_based_color_scheme_1.png',
+        ),
+    );
+    expect(
+      loadColorSchemeCalls.last.$2,
+      Brightness.dark,
+    );
+
+    await tester.pump(kThemeChangeDuration);
+
+    themeData = Theme.of(tester.element(find.byType(Scaffold)));
+
+    expect(themeData.colorScheme.primary, const Color(0xffbfc2ff));
+    expect(themeData.colorScheme.secondary, const Color(0xffc5c4dd));
+  });
+
+  testWidgets('Tapping an image loads a new color scheme', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      example.DynamicColorExample(
+        loadColorScheme: fakeColorSchemeLoader,
+      ),
+    );
+    await tester.pump();
+
+    await tester.tapAt(tester.getCenter(find.byType(Image).at(3)));
+    await tester.pump();
+
+    expect(loadColorSchemeCalls, hasLength(2));
+    expect(
+      loadColorSchemeCalls.last.$1,
+      isA<NetworkImage>()
+        .having(
+          (NetworkImage provider) => provider.url,
+          'url',
+          'https://flutter.github.io/assets-for-api-docs/assets/material/content_based_color_scheme_4.png',
+        ),
+    );
+    expect(
+      loadColorSchemeCalls.last.$2,
+      Brightness.light,
+    );
+
+    await tester.pump(kThemeChangeDuration);
+
+    final ThemeData themeData = Theme.of(tester.element(find.byType(Scaffold)));
+
+    expect(themeData.colorScheme.primary, const Color(0xff406836));
+    expect(themeData.colorScheme.secondary, const Color(0xff54634d));
+  });
+}