Add test for inherited_notifier.0.dart (#150344)

Contributes to flutter/flutter#130459

It adds a test for
- `examples/api/lib/widgets/inherited_notifier/inherited_notifier.0.dart`

dev/bots/check_code_samples.dart

@@ -385,7 +385,6 @@ final Set<String> _knownMissingTests = <String>{
   'examples/api/test/widgets/color_filter/color_filtered.0_test.dart',
   'examples/api/test/widgets/focus_scope/focus_scope.0_test.dart',
   'examples/api/test/widgets/scroll_view/custom_scroll_view.1_test.dart',
-  'examples/api/test/widgets/inherited_notifier/inherited_notifier.0_test.dart',
   'examples/api/test/animation/curves/curve2_d.0_test.dart',
   'examples/api/test/gestures/pointer_signal_resolver/pointer_signal_resolver.0_test.dart',
 };

examples/api/test/widgets/inherited_notifier/inherited_notifier.0_test.dart

@@ -0,0 +1,60 @@
+// 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:math' as math;
+
+import 'package:flutter/material.dart';
+import 'package:flutter_api_samples/widgets/inherited_notifier/inherited_notifier.0.dart' as example;
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  testWidgets('It rotates the spinners', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      const example.InheritedNotifierExampleApp(),
+    );
+
+    final Iterable<Transform> widgets = tester.widgetList<Transform>(
+      find.ancestor(
+        of: find.text('Whee!'),
+        matching: find.byType(Transform),
+      ),
+    );
+
+    Matcher transformMatcher(Matrix4 matrix) {
+      return everyElement(isA<Transform>().having((Transform widget) => widget.transform, 'transform', matrix));
+    }
+
+    expect(widgets, transformMatcher(Matrix4.identity()));
+
+    await tester.pump(const Duration(seconds: 1));
+    expect(widgets, transformMatcher(Matrix4.rotationZ(0.2 * math.pi)));
+
+    await tester.pump(const Duration(seconds: 1));
+    expect(widgets, transformMatcher(Matrix4.rotationZ(0.4 * math.pi)));
+
+    await tester.pump(const Duration(seconds: 1));
+    expect(widgets, transformMatcher(Matrix4.rotationZ(0.6 * math.pi)));
+
+    await tester.pump(const Duration(seconds: 1));
+    expect(widgets, transformMatcher(Matrix4.rotationZ(0.8 * math.pi)));
+
+    await tester.pump(const Duration(seconds: 1));
+    expect(widgets, transformMatcher(Matrix4.identity()..storage[0] = -1..storage[5] = -1));
+
+    await tester.pump(const Duration(seconds: 1));
+    expect(widgets, transformMatcher(Matrix4.rotationZ(1.2 * math.pi)));
+
+    await tester.pump(const Duration(seconds: 1));
+    expect(widgets, transformMatcher(Matrix4.rotationZ(1.4 * math.pi)));
+
+    await tester.pump(const Duration(seconds: 1));
+    expect(widgets, transformMatcher(Matrix4.rotationZ(1.6 * math.pi)));
+
+    await tester.pump(const Duration(seconds: 1));
+    expect(widgets, transformMatcher(Matrix4.rotationZ(1.8 * math.pi)));
+
+    await tester.pump(const Duration(seconds: 1));
+    expect(widgets, transformMatcher(Matrix4.identity()));
+  });
+}