Test Material buttons against a11y contrast guidelines (#32050)

packages/flutter/test/material/flat_button_test.dart

@@ -9,7 +9,7 @@ import 'package:flutter/rendering.dart';
 import '../rendering/mock_canvas.dart';
 
 void main() {
-  testWidgets('FlatButton implements debugFillDescription', (WidgetTester tester) async {
+  testWidgets('FlatButton implements debugFillProperties', (WidgetTester tester) async {
     final DiagnosticPropertiesBuilder builder = DiagnosticPropertiesBuilder();
     FlatButton(
         onPressed: () { },
@@ -32,6 +32,33 @@ void main() {
     ]);
   });
 
+  testWidgets('Default FlatButton meets a11y contrast guidelines', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Scaffold(
+          body: Center(
+            child: FlatButton(
+              child: const Text('FlatButton'),
+              onPressed: () { },
+            ),
+          ),
+        ),
+      ),
+    );
+
+    // Default, not disabled.
+    await expectLater(tester, meetsGuideline(textContrastGuideline));
+
+    // Highlighted (pressed).
+    final Offset center = tester.getCenter(find.byType(FlatButton));
+    await tester.startGesture(center);
+    await tester.pump(); // Start the splash and highlight animations.
+    await tester.pump(const Duration(milliseconds: 800)); // Wait for splash and highlight to be well under way.
+    await expectLater(tester, meetsGuideline(textContrastGuideline));
+  },
+    semanticsEnabled: true,
+  );
+
   testWidgets('FlatButton has no clip by default', (WidgetTester tester) async {
     await tester.pumpWidget(
       Directionality(

packages/flutter/test/material/material_button_test.dart

@@ -0,0 +1,37 @@
+// Copyright 2019 The Chromium 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 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter/rendering.dart';
+
+void main() {
+  testWidgets('Default MaterialButton meets a11y contrast guidelines', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Scaffold(
+          body: Center(
+            child: MaterialButton(
+              child: const Text('MaterialButton'),
+              onPressed: () { },
+            ),
+          ),
+        ),
+      ),
+    );
+
+    // Default, not disabled.
+    await expectLater(tester, meetsGuideline(textContrastGuideline));
+
+    // Highlighted (pressed).
+    final Offset center = tester.getCenter(find.byType(MaterialButton));
+    await tester.startGesture(center);
+    await tester.pump(); // Start the splash and highlight animations.
+    await tester.pump(const Duration(milliseconds: 800)); // Wait for splash and highlight to be well under way.
+    await expectLater(tester, meetsGuideline(textContrastGuideline));
+  },
+    semanticsEnabled: true,
+  );
+
+}

packages/flutter/test/material/outline_button_test.dart

@@ -10,27 +10,58 @@ import '../rendering/mock_canvas.dart';
 import '../widgets/semantics_tester.dart';
 
 void main() {
-    PhysicalModelLayer findPhysicalLayer(Element element) {
+  testWidgets('OutlineButton implements debugFillProperties', (WidgetTester tester) async {
-      expect(element, isNotNull);
+    final DiagnosticPropertiesBuilder builder = DiagnosticPropertiesBuilder();
-      RenderObject object = element.renderObject;
+    OutlineButton(
-      while (object != null && object is! RenderRepaintBoundary && object is! RenderView) {
+      onPressed: () { },
-        object = object.parent;
+      textColor: const Color(0xFF00FF00),
-      }
+      disabledTextColor: const Color(0xFFFF0000),
-      expect(object.debugLayer, isNotNull);
+      color: const Color(0xFF000000),
-      expect(object.debugLayer.firstChild, isInstanceOf<PhysicalModelLayer>());
+      highlightColor: const Color(0xFF1565C0),
-      final PhysicalModelLayer layer = object.debugLayer.firstChild;
+      splashColor: const Color(0xFF9E9E9E),
-      return layer.firstChild is PhysicalModelLayer ? layer.firstChild : layer;
+      child: const Text('Hello'),
-    }
+    ).debugFillProperties(builder);
+
+    final List<String> description = builder.properties
+      .where((DiagnosticsNode node) => !node.isFiltered(DiagnosticLevel.info))
+      .map((DiagnosticsNode node) => node.toString()).toList();
+
+    expect(description, <String>[
+      'textColor: Color(0xff00ff00)',
+      'disabledTextColor: Color(0xffff0000)',
+      'color: Color(0xff000000)',
+      'highlightColor: Color(0xff1565c0)',
+      'splashColor: Color(0xff9e9e9e)',
+    ]);
+  });
+
+  testWidgets('Default OutlineButton meets a11y contrast guidelines', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Scaffold(
+          body: Center(
+            child: OutlineButton(
+              child: const Text('OutlineButton'),
+              onPressed: () { },
+            ),
+          ),
+        ),
+      ),
+    );
+
+    // Default, not disabled.
+    await expectLater(tester, meetsGuideline(textContrastGuideline));
+
+    // Highlighted (pressed).
+    final Offset center = tester.getCenter(find.byType(OutlineButton));
+    await tester.startGesture(center);
+    await tester.pump(); // Start the splash and highlight animations.
+    await tester.pump(const Duration(milliseconds: 800)); // Wait for splash and highlight to be well under way.
+    await expectLater(tester, meetsGuideline(textContrastGuideline));
+  },
+    semanticsEnabled: true,
+  );
 
-    void checkPhysicalLayer(Element element, Color expectedColor, {Path clipPath, Rect clipRect}) {
-      final PhysicalModelLayer expectedLayer = findPhysicalLayer(element);
-      expect(expectedLayer.elevation, 0.0);
-      expect(expectedLayer.color, expectedColor);
-      if (clipPath != null) {
-        expect(clipRect, isNotNull);
-        expect(expectedLayer.clipPath, coversSameAreaAs(clipPath, areaToCompare: clipRect.inflate(10.0)));
-      }
-    }
   testWidgets('Outline button responds to tap when enabled', (WidgetTester tester) async {
     int pressedCount = 0;
 
@@ -136,7 +167,7 @@ void main() {
       outlineButton,
       paints
         ..path(color: disabledBorderColor, strokeWidth: borderWidth));
-    checkPhysicalLayer(
+    _checkPhysicalLayer(
       tester.element(outlineButton),
       const Color(0),
       clipPath: clipPath,
@@ -158,7 +189,7 @@ void main() {
       paints
         ..path(color: borderColor, strokeWidth: borderWidth));
     // initially, the interior of the button is transparent
-    checkPhysicalLayer(
+    _checkPhysicalLayer(
       tester.element(outlineButton),
       fillColor.withAlpha(0x00),
       clipPath: clipPath,
@@ -175,7 +206,7 @@ void main() {
       outlineButton,
       paints
         ..path(color: highlightedBorderColor, strokeWidth: borderWidth));
-    checkPhysicalLayer(
+    _checkPhysicalLayer(
       tester.element(outlineButton),
       fillColor.withAlpha(0xFF),
       clipPath: clipPath,
@@ -189,7 +220,7 @@ void main() {
       outlineButton,
       paints
         ..path(color: borderColor, strokeWidth: borderWidth));
-    checkPhysicalLayer(
+    _checkPhysicalLayer(
       tester.element(outlineButton),
       fillColor.withAlpha(0x00),
       clipPath: clipPath,
@@ -331,31 +362,6 @@ void main() {
     expect(tester.getSize(find.byType(Text)).height, equals(42.0));
   });
 
-  testWidgets('OutlineButton implements debugFillProperties', (WidgetTester tester) async {
-    final DiagnosticPropertiesBuilder builder = DiagnosticPropertiesBuilder();
-    OutlineButton(
-      onPressed: () { },
-      textColor: const Color(0xFF00FF00),
-      disabledTextColor: const Color(0xFFFF0000),
-      color: const Color(0xFF000000),
-      highlightColor: const Color(0xFF1565C0),
-      splashColor: const Color(0xFF9E9E9E),
-      child: const Text('Hello'),
-    ).debugFillProperties(builder);
-
-    final List<String> description = builder.properties
-      .where((DiagnosticsNode node) => !node.isFiltered(DiagnosticLevel.info))
-      .map((DiagnosticsNode node) => node.toString()).toList();
-
-    expect(description, <String>[
-      'textColor: Color(0xff00ff00)',
-      'disabledTextColor: Color(0xffff0000)',
-      'color: Color(0xff000000)',
-      'highlightColor: Color(0xff1565c0)',
-      'splashColor: Color(0xff9e9e9e)',
-    ]);
-  });
-
   testWidgets('OutlineButton pressed fillColor default', (WidgetTester tester) async {
     Widget buildFrame(ThemeData theme) {
       return MaterialApp(
@@ -385,18 +391,18 @@ void main() {
     Color fillColor = Colors.grey[850];
 
     // Initially the interior of the button is transparent.
-    checkPhysicalLayer(buttonElement, fillColor.withAlpha(0x00));
+    _checkPhysicalLayer(buttonElement, fillColor.withAlpha(0x00));
 
     // Tap-press gesture on the button triggers the fill animation.
     TestGesture gesture = await tester.startGesture(center);
     await tester.pump(); // Start the button fill animation.
     await tester.pump(const Duration(milliseconds: 200)); // Animation is complete.
-    checkPhysicalLayer(buttonElement, fillColor.withAlpha(0xFF));
+    _checkPhysicalLayer(buttonElement, fillColor.withAlpha(0xFF));
 
     // Tap gesture completes, button returns to its initial configuration.
     await gesture.up();
     await tester.pumpAndSettle();
-    checkPhysicalLayer(buttonElement, fillColor.withAlpha(0x00));
+    _checkPhysicalLayer(buttonElement, fillColor.withAlpha(0x00));
 
     await tester.pumpWidget(buildFrame(ThemeData.light()));
     await tester.pumpAndSettle(); // Finish the theme change animation.
@@ -412,11 +418,33 @@ void main() {
     gesture = await tester.startGesture(center);
     await tester.pump(); // Start the button fill animation.
     await tester.pump(const Duration(milliseconds: 200)); // Animation is complete.
-    checkPhysicalLayer(buttonElement, fillColor.withAlpha(0xFF));
+    _checkPhysicalLayer(buttonElement, fillColor.withAlpha(0xFF));
 
     // Tap gesture completes, button returns to its initial configuration.
     await gesture.up();
     await tester.pumpAndSettle();
-    checkPhysicalLayer(buttonElement, fillColor.withAlpha(0x00));
+    _checkPhysicalLayer(buttonElement, fillColor.withAlpha(0x00));
   });
 }
+
+PhysicalModelLayer _findPhysicalLayer(Element element) {
+  expect(element, isNotNull);
+  RenderObject object = element.renderObject;
+  while (object != null && object is! RenderRepaintBoundary && object is! RenderView) {
+    object = object.parent;
+  }
+  expect(object.debugLayer, isNotNull);
+  expect(object.debugLayer.firstChild, isInstanceOf<PhysicalModelLayer>());
+  final PhysicalModelLayer layer = object.debugLayer.firstChild;
+  return layer.firstChild is PhysicalModelLayer ? layer.firstChild : layer;
+}
+
+void _checkPhysicalLayer(Element element, Color expectedColor, { Path clipPath, Rect clipRect }) {
+  final PhysicalModelLayer expectedLayer = _findPhysicalLayer(element);
+  expect(expectedLayer.elevation, 0.0);
+  expect(expectedLayer.color, expectedColor);
+  if (clipPath != null) {
+    expect(clipRect, isNotNull);
+    expect(expectedLayer.clipPath, coversSameAreaAs(clipPath, areaToCompare: clipRect.inflate(10.0)));
+  }
+}

packages/flutter/test/material/raised_button_test.dart

@@ -0,0 +1,63 @@
+// Copyright 2019 The Chromium 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 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter/rendering.dart';
+
+void main() {
+  testWidgets('RaisedButton implements debugFillProperties', (WidgetTester tester) async {
+    final DiagnosticPropertiesBuilder builder = DiagnosticPropertiesBuilder();
+    RaisedButton(
+      onPressed: () { },
+      textColor: const Color(0xFF00FF00),
+      disabledTextColor: const Color(0xFFFF0000),
+      color: const Color(0xFF000000),
+      highlightColor: const Color(0xFF1565C0),
+      splashColor: const Color(0xFF9E9E9E),
+      child: const Text('Hello'),
+    ).debugFillProperties(builder);
+
+    final List<String> description = builder.properties
+      .where((DiagnosticsNode node) => !node.isFiltered(DiagnosticLevel.info))
+      .map((DiagnosticsNode node) => node.toString()).toList();
+
+    expect(description, <String>[
+      'textColor: Color(0xff00ff00)',
+      'disabledTextColor: Color(0xffff0000)',
+      'color: Color(0xff000000)',
+      'highlightColor: Color(0xff1565c0)',
+      'splashColor: Color(0xff9e9e9e)',
+    ]);
+  });
+
+  testWidgets('Default RaisedButton meets a11y contrast guidelines', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Scaffold(
+          body: Center(
+            child: RaisedButton(
+              child: const Text('RaisedButton'),
+              onPressed: () { },
+            ),
+          ),
+        ),
+      ),
+    );
+
+    // Default, not disabled.
+    await expectLater(tester, meetsGuideline(textContrastGuideline));
+
+    // Highlighted (pressed).
+    final Offset center = tester.getCenter(find.byType(RaisedButton));
+    await tester.startGesture(center);
+    await tester.pump(); // Start the splash and highlight animations.
+    await tester.pump(const Duration(milliseconds: 800)); // Wait for splash and highlight to be well under way.
+    await expectLater(tester, meetsGuideline(textContrastGuideline));
+  },
+    semanticsEnabled: true,
+  );
+
+
+}