elevated_button_test.dart

// 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.

// @dart = 2.8

import 'package:flutter/gestures.dart';
import 'package:flutter/material.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:flutter/rendering.dart';

import '../rendering/mock_canvas.dart';
import '../widgets/semantics_tester.dart';

void main() {
  testWidgets('ElevatedButton defaults', (WidgetTester tester) async {
    const ColorScheme colorScheme = ColorScheme.light();

    // Enabled ElevatedButton
    await tester.pumpWidget(
      MaterialApp(
        theme: ThemeData.from(colorScheme: colorScheme),
        home: Center(
          child: ElevatedButton(
            onPressed: () { },
            child: const Text('button'),
          ),
        ),
      ),
    );

    final Finder rawButtonMaterial = find.descendant(
      of: find.byType(ElevatedButton),
      matching: find.byType(Material),
    );


    Material material = tester.widget<Material>(rawButtonMaterial);
    expect(material.animationDuration, const Duration(milliseconds: 200));
    expect(material.borderOnForeground, true);
    expect(material.borderRadius, null);
    expect(material.clipBehavior, Clip.none);
    expect(material.color, colorScheme.primary);
    expect(material.elevation, 2);
    expect(material.shadowColor, const Color(0xff000000));
    expect(material.shape, RoundedRectangleBorder(borderRadius: BorderRadius.circular(4)));
    expect(material.textStyle.color, colorScheme.onPrimary);
    expect(material.textStyle.fontFamily, 'Roboto');
    expect(material.textStyle.fontSize, 14);
    expect(material.textStyle.fontWeight, FontWeight.w500);
    expect(material.type, MaterialType.button);

    final Offset center = tester.getCenter(find.byType(ElevatedButton));
    final TestGesture gesture = await tester.startGesture(center);
    await tester.pump(); // start the splash animation
    await tester.pump(const Duration(milliseconds: 100)); // splash is underway
    final RenderObject inkFeatures = tester.allRenderObjects.firstWhere((RenderObject object) => object.runtimeType.toString() == '_RenderInkFeatures');
    expect(inkFeatures, paints..circle(color: colorScheme.onPrimary.withAlpha(0x3d))); // splash color is onPrimary(0.24)

    // Only elevation changes when enabled and pressed.
    material = tester.widget<Material>(rawButtonMaterial);
    expect(material.animationDuration, const Duration(milliseconds: 200));
    expect(material.borderOnForeground, true);
    expect(material.borderRadius, null);
    expect(material.clipBehavior, Clip.none);
    expect(material.color, colorScheme.primary);
    expect(material.elevation, 8);
    expect(material.shadowColor, const Color(0xff000000));
    expect(material.shape, RoundedRectangleBorder(borderRadius: BorderRadius.circular(4)));
    expect(material.textStyle.color, colorScheme.onPrimary);
    expect(material.textStyle.fontFamily, 'Roboto');
    expect(material.textStyle.fontSize, 14);
    expect(material.textStyle.fontWeight, FontWeight.w500);
    expect(material.type, MaterialType.button);

    await gesture.up();
    await tester.pumpAndSettle();

    // Disabled ElevatedButton
    await tester.pumpWidget(
      MaterialApp(
        theme: ThemeData.from(colorScheme: colorScheme),
        home: const Center(
          child: ElevatedButton(
            onPressed: null,
            child: Text('button'),
          ),
        ),
      ),
    );

    // Finish the elevation animation, final background color change.
    await tester.pumpAndSettle();

    material = tester.widget<Material>(rawButtonMaterial);
    expect(material.animationDuration, const Duration(milliseconds: 200));
    expect(material.borderOnForeground, true);
    expect(material.borderRadius, null);
    expect(material.clipBehavior, Clip.none);
    expect(material.color, colorScheme.onSurface.withOpacity(0.12));
    expect(material.elevation, 0.0);
    expect(material.shadowColor, const Color(0xff000000));
    expect(material.shape, RoundedRectangleBorder(borderRadius: BorderRadius.circular(4)));
    expect(material.textStyle.color, colorScheme.onSurface.withOpacity(0.38));
    expect(material.textStyle.fontFamily, 'Roboto');
    expect(material.textStyle.fontSize, 14);
    expect(material.textStyle.fontWeight, FontWeight.w500);
    expect(material.type, MaterialType.button);
  });

  testWidgets('Default ElevatedButton meets a11y contrast guidelines', (WidgetTester tester) async {
    final FocusNode focusNode = FocusNode();

    await tester.pumpWidget(
      MaterialApp(
        theme: ThemeData.from(colorScheme: const ColorScheme.light()),
        home: Scaffold(
          body: Center(
            child: ElevatedButton(
              child: const Text('ElevatedButton'),
              onPressed: () { },
              focusNode: focusNode,
            ),
          ),
        ),
      ),
    );

    // Default, not disabled.
    await expectLater(tester, meetsGuideline(textContrastGuideline));

    // Focused.
    focusNode.requestFocus();
    await tester.pumpAndSettle();
    await expectLater(tester, meetsGuideline(textContrastGuideline));

    // Hovered.
    final Offset center = tester.getCenter(find.byType(ElevatedButton));
    final TestGesture gesture = await tester.createGesture(
      kind: PointerDeviceKind.mouse,
    );
    await gesture.addPointer();
    addTearDown(gesture.removePointer);
    await gesture.moveTo(center);
    await tester.pumpAndSettle();
    await expectLater(tester, meetsGuideline(textContrastGuideline));
  },
    skip: isBrowser, // https://github.com/flutter/flutter/issues/44115
    semanticsEnabled: true,
  );


  testWidgets('ElevatedButton uses stateful color for text color in different states', (WidgetTester tester) async {
    final FocusNode focusNode = FocusNode();

    const Color pressedColor = Color(0x00000001);
    const Color hoverColor = Color(0x00000002);
    const Color focusedColor = Color(0x00000003);
    const Color defaultColor = Color(0x00000004);

    Color getTextColor(Set<MaterialState> states) {
      if (states.contains(MaterialState.pressed)) {
        return pressedColor;
      }
      if (states.contains(MaterialState.hovered)) {
        return hoverColor;
      }
      if (states.contains(MaterialState.focused)) {
        return focusedColor;
      }
      return defaultColor;
    }

    await tester.pumpWidget(
      MaterialApp(
        home: Scaffold(
          body: Center(
            child: ElevatedButtonTheme(
              data: ElevatedButtonThemeData(
                style: ButtonStyle(
                  foregroundColor: MaterialStateProperty.resolveWith<Color>(getTextColor),
                ),
              ),
              child: Builder(
                builder: (BuildContext context) {
                  return ElevatedButton(
                    child: const Text('ElevatedButton'),
                    onPressed: () {},
                    focusNode: focusNode,
                  );
                },
              ),
            ),
          ),
        ),
      ),
    );

    Color textColor() {
      return tester.renderObject<RenderParagraph>(find.text('ElevatedButton')).text.style.color;
    }

    // Default, not disabled.
    expect(textColor(), equals(defaultColor));

    // Focused.
    focusNode.requestFocus();
    await tester.pumpAndSettle();
    expect(textColor(), focusedColor);

    // Hovered.
    final Offset center = tester.getCenter(find.byType(ElevatedButton));
    final TestGesture gesture = await tester.createGesture(
      kind: PointerDeviceKind.mouse,
    );
    await gesture.addPointer();
    addTearDown(gesture.removePointer);
    await gesture.moveTo(center);
    await tester.pumpAndSettle();
    expect(textColor(), hoverColor);

    // Highlighted (pressed).
    await gesture.down(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.
    expect(textColor(), pressedColor);
  });


  testWidgets('ElevatedButton uses stateful color for icon color in different states', (WidgetTester tester) async {
    final FocusNode focusNode = FocusNode();
    final Key buttonKey = UniqueKey();

    const Color pressedColor = Color(0x00000001);
    const Color hoverColor = Color(0x00000002);
    const Color focusedColor = Color(0x00000003);
    const Color defaultColor = Color(0x00000004);

    Color getTextColor(Set<MaterialState> states) {
      if (states.contains(MaterialState.pressed)) {
        return pressedColor;
      }
      if (states.contains(MaterialState.hovered)) {
        return hoverColor;
      }
      if (states.contains(MaterialState.focused)) {
        return focusedColor;
      }
      return defaultColor;
    }

    await tester.pumpWidget(
      MaterialApp(
        home: Scaffold(
          body: Center(
            child: ElevatedButtonTheme(
              data: ElevatedButtonThemeData(
                style: ButtonStyle(
                  foregroundColor: MaterialStateProperty.resolveWith<Color>(getTextColor),
                ),
              ),
              child: Builder(
                builder: (BuildContext context) {
                  return ElevatedButton.icon(
                    key: buttonKey,
                    icon: const Icon(Icons.add),
                    label: const Text('ElevatedButton'),
                    onPressed: () {},
                    focusNode: focusNode,
                  );
                },
              ),
            ),
          ),
        ),
      ),
    );

    Color iconColor() => _iconStyle(tester, Icons.add).color;
    // Default, not disabled.
    expect(iconColor(), equals(defaultColor));

    // Focused.
    focusNode.requestFocus();
    await tester.pumpAndSettle();
    expect(iconColor(), focusedColor);

    // Hovered.
    final Offset center = tester.getCenter(find.byKey(buttonKey));
    final TestGesture gesture = await tester.createGesture(
      kind: PointerDeviceKind.mouse,
    );
    await gesture.addPointer();
    addTearDown(gesture.removePointer);
    await gesture.moveTo(center);
    await tester.pumpAndSettle();
    expect(iconColor(), hoverColor);

    // Highlighted (pressed).
    await gesture.down(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.
    expect(iconColor(), pressedColor);
  });

  testWidgets('ElevatedButton onPressed and onLongPress callbacks are correctly called when non-null', (WidgetTester tester) async {
    bool wasPressed;
    Finder elevatedButton;

    Widget buildFrame({ VoidCallback onPressed, VoidCallback onLongPress }) {
      return Directionality(
        textDirection: TextDirection.ltr,
        child: ElevatedButton(
          child: const Text('button'),
          onPressed: onPressed,
          onLongPress: onLongPress,
        ),
      );
    }

    // onPressed not null, onLongPress null.
    wasPressed = false;
    await tester.pumpWidget(
      buildFrame(onPressed: () { wasPressed = true; }, onLongPress: null),
    );
    elevatedButton = find.byType(ElevatedButton);
    expect(tester.widget<ElevatedButton>(elevatedButton).enabled, true);
    await tester.tap(elevatedButton);
    expect(wasPressed, true);

    // onPressed null, onLongPress not null.
    wasPressed = false;
    await tester.pumpWidget(
      buildFrame(onPressed: null, onLongPress: () { wasPressed = true; }),
    );
    elevatedButton = find.byType(ElevatedButton);
    expect(tester.widget<ElevatedButton>(elevatedButton).enabled, true);
    await tester.longPress(elevatedButton);
    expect(wasPressed, true);

    // onPressed null, onLongPress null.
    await tester.pumpWidget(
      buildFrame(onPressed: null, onLongPress: null),
    );
    elevatedButton = find.byType(ElevatedButton);
    expect(tester.widget<ElevatedButton>(elevatedButton).enabled, false);
  });

  testWidgets('ElevatedButton onPressed and onLongPress callbacks are distinctly recognized', (WidgetTester tester) async {
    bool didPressButton = false;
    bool didLongPressButton = false;

    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
        child: ElevatedButton(
          onPressed: () {
            didPressButton = true;
          },
          onLongPress: () {
            didLongPressButton = true;
          },
          child: const Text('button'),
        ),
      ),
    );

    final Finder elevatedButton = find.byType(ElevatedButton);
    expect(tester.widget<ElevatedButton>(elevatedButton).enabled, true);

    expect(didPressButton, isFalse);
    await tester.tap(elevatedButton);
    expect(didPressButton, isTrue);

    expect(didLongPressButton, isFalse);
    await tester.longPress(elevatedButton);
    expect(didLongPressButton, isTrue);
  });

  testWidgets('Does ElevatedButton work with hover', (WidgetTester tester) async {
    const Color hoverColor = Color(0xff001122);

    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
        child: ElevatedButton(
          style: ButtonStyle(
            overlayColor: MaterialStateProperty.resolveWith<Color>((Set<MaterialState> states) {
              return states.contains(MaterialState.hovered) ? hoverColor : null;
            }),
          ),
          onPressed: () { },
          child: const Text('button'),
        ),
      ),
    );

    final TestGesture gesture = await tester.createGesture(kind: PointerDeviceKind.mouse);
    await gesture.addPointer();
    await gesture.moveTo(tester.getCenter(find.byType(ElevatedButton)));
    await tester.pumpAndSettle();

    final RenderObject inkFeatures = tester.allRenderObjects.firstWhere((RenderObject object) => object.runtimeType.toString() == '_RenderInkFeatures');
    expect(inkFeatures, paints..rect(color: hoverColor));

    await gesture.removePointer();
  });

  testWidgets('Does ElevatedButton work with focus', (WidgetTester tester) async {
    const Color focusColor = Color(0xff001122);

    final FocusNode focusNode = FocusNode(debugLabel: 'ElevatedButton Node');
    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
        child: ElevatedButton(
          style: ButtonStyle(
            overlayColor: MaterialStateProperty.resolveWith<Color>((Set<MaterialState> states) {
              return states.contains(MaterialState.focused) ? focusColor : null;
            }),
          ),
          focusNode: focusNode,
          onPressed: () { },
          child: const Text('button'),
        ),
      ),
    );

    FocusManager.instance.highlightStrategy = FocusHighlightStrategy.alwaysTraditional;
    focusNode.requestFocus();
    await tester.pumpAndSettle();

    final RenderObject inkFeatures = tester.allRenderObjects.firstWhere((RenderObject object) => object.runtimeType.toString() == '_RenderInkFeatures');
    expect(inkFeatures, paints..rect(color: focusColor));
  });

  testWidgets('Does ElevatedButton work with autofocus', (WidgetTester tester) async {
    const Color focusColor = Color(0xff001122);

    Color getOverlayColor(Set<MaterialState> states) {
      return states.contains(MaterialState.focused) ? focusColor : null;
    }

    final FocusNode focusNode = FocusNode(debugLabel: 'ElevatedButton Node');
    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
        child: ElevatedButton(
          autofocus: true,
          style: ButtonStyle(
            overlayColor: MaterialStateProperty.resolveWith<Color>(getOverlayColor),
          ),
          focusNode: focusNode,
          onPressed: () { },
          child: const Text('button'),
        ),
      ),
    );

    FocusManager.instance.highlightStrategy = FocusHighlightStrategy.alwaysTraditional;
    await tester.pumpAndSettle();

    final RenderObject inkFeatures = tester.allRenderObjects.firstWhere((RenderObject object) => object.runtimeType.toString() == '_RenderInkFeatures');
    expect(inkFeatures, paints..rect(color: focusColor));
  });

  testWidgets('Does ElevatedButton contribute semantics', (WidgetTester tester) async {
    final SemanticsTester semantics = SemanticsTester(tester);
    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
        child: Material(
          child: Center(
            child: ElevatedButton(
              style: ButtonStyle(
                // Specifying minimumSize to mimic the original minimumSize for
                // RaisedButton so that the semantics tree's rect and transform
                // match the original version of this test.
                minimumSize: MaterialStateProperty.all<Size>(const Size(88, 36)),
              ),
              onPressed: () { },
              child: const Text('ABC'),
            ),
          ),
        ),
      ),
    );

    expect(semantics, hasSemantics(
      TestSemantics.root(
        children: <TestSemantics>[
          TestSemantics.rootChild(
            actions: <SemanticsAction>[
              SemanticsAction.tap,
            ],
            label: 'ABC',
            rect: const Rect.fromLTRB(0.0, 0.0, 88.0, 48.0),
            transform: Matrix4.translationValues(356.0, 276.0, 0.0),
            flags: <SemanticsFlag>[
              SemanticsFlag.hasEnabledState,
              SemanticsFlag.isButton,
              SemanticsFlag.isEnabled,
              SemanticsFlag.isFocusable,
            ],
          ),
        ],
      ),
      ignoreId: true,
    ));

    semantics.dispose();
  });

  testWidgets('ElevatedButton size is configurable by ThemeData.materialTapTargetSize', (WidgetTester tester) async {
    final ButtonStyle style = ButtonStyle(
      // Specifying minimumSize to mimic the original minimumSize for
      // RaisedButton so that the corresponding button size matches
      // the original version of this test.
      minimumSize: MaterialStateProperty.all<Size>(const Size(88, 36)),
    );

    Widget buildFrame(MaterialTapTargetSize tapTargetSize, Key key) {
      return Theme(
        data: ThemeData(materialTapTargetSize: tapTargetSize),
        child: Directionality(
          textDirection: TextDirection.ltr,
          child: Material(
            child: Center(
              child: ElevatedButton(
                key: key,
                style: style,
                child: const SizedBox(width: 50.0, height: 8.0),
                onPressed: () { },
              ),
            ),
          ),
        ),
      );
    }

    final Key key1 = UniqueKey();
    await tester.pumpWidget(buildFrame(MaterialTapTargetSize.padded, key1));
    expect(tester.getSize(find.byKey(key1)), const Size(88.0, 48.0));

    final Key key2 = UniqueKey();
    await tester.pumpWidget(buildFrame(MaterialTapTargetSize.shrinkWrap, key2));
    expect(tester.getSize(find.byKey(key2)), const Size(88.0, 36.0));
  });

  testWidgets('ElevatedButton has no clip by default', (WidgetTester tester) async {
    await tester.pumpWidget(
      Directionality(
        textDirection: TextDirection.ltr,
        child: Material(
          child: ElevatedButton(
            onPressed: () { /* to make sure the button is enabled */ },
            child: const Text('button'),
          ),
        ),
      ),
    );

    expect(
      tester.renderObject(find.byType(ElevatedButton)),
      paintsExactlyCountTimes(#clipPath, 0),
    );
  });

  testWidgets('ElevatedButton responds to density changes.', (WidgetTester tester) async {
    const Key key = Key('test');
    const Key childKey = Key('test child');

    Future<void> buildTest(VisualDensity visualDensity, {bool useText = false}) async {
      return await tester.pumpWidget(
        MaterialApp(
          home: Directionality(
            textDirection: TextDirection.rtl,
            child: Center(
              child: ElevatedButton(
                style: ButtonStyle(
                  visualDensity: visualDensity,
                  // Specifying minimumSize to mimic the original minimumSize for
                  // RaisedButton so that the corresponding button size matches
                  // the original version of this test.
                  minimumSize: MaterialStateProperty.all<Size>(const Size(88, 36)),
                ),
                key: key,
                onPressed: () {},
                child: useText
                  ? const Text('Text', key: childKey)
                  : Container(key: childKey, width: 100, height: 100, color: const Color(0xffff0000)),
              ),
            ),
          ),
        ),
      );
    }

    await buildTest(const VisualDensity());
    final RenderBox box = tester.renderObject(find.byKey(key));
    Rect childRect = tester.getRect(find.byKey(childKey));
    await tester.pumpAndSettle();
    expect(box.size, equals(const Size(132, 100)));
    expect(childRect, equals(const Rect.fromLTRB(350, 250, 450, 350)));

    await buildTest(const VisualDensity(horizontal: 3.0, vertical: 3.0));
    await tester.pumpAndSettle();
    childRect = tester.getRect(find.byKey(childKey));
    expect(box.size, equals(const Size(156, 124)));
    expect(childRect, equals(const Rect.fromLTRB(350, 250, 450, 350)));

    await buildTest(const VisualDensity(horizontal: -3.0, vertical: -3.0));
    await tester.pumpAndSettle();
    childRect = tester.getRect(find.byKey(childKey));
    expect(box.size, equals(const Size(108, 100)));
    expect(childRect, equals(const Rect.fromLTRB(350, 250, 450, 350)));

    await buildTest(const VisualDensity(), useText: true);
    await tester.pumpAndSettle();
    childRect = tester.getRect(find.byKey(childKey));
    expect(box.size, equals(const Size(88, 48)));
    expect(childRect, equals(const Rect.fromLTRB(372.0, 293.0, 428.0, 307.0)));

    await buildTest(const VisualDensity(horizontal: 3.0, vertical: 3.0), useText: true);
    await tester.pumpAndSettle();
    childRect = tester.getRect(find.byKey(childKey));
    expect(box.size, equals(const Size(112, 60)));
    expect(childRect, equals(const Rect.fromLTRB(372.0, 293.0, 428.0, 307.0)));

    await buildTest(const VisualDensity(horizontal: -3.0, vertical: -3.0), useText: true);
    await tester.pumpAndSettle();
    childRect = tester.getRect(find.byKey(childKey));
    expect(box.size, equals(const Size(76, 36)));
    expect(childRect, equals(const Rect.fromLTRB(372.0, 293.0, 428.0, 307.0)));
  });

  testWidgets('ElevatedButton.icon responds to applied padding', (WidgetTester tester) async {
    const Key buttonKey = Key('test');
    const Key labelKey = Key('label');
    await tester.pumpWidget(
      // When textDirection is set to TextDirection.ltr, the label appears on the
      // right side of the icon. This is important in determining whether the
      // horizontal padding is applied correctly later on
      Directionality(
        textDirection: TextDirection.ltr,
        child: Material(
          child: Center(
            child: ElevatedButton.icon(
              key: buttonKey,
              style: ButtonStyle(
                padding: MaterialStateProperty.all<EdgeInsets>(const EdgeInsets.fromLTRB(16, 5, 10, 12)),
              ),
              onPressed: () {},
              icon: const Icon(Icons.add),
              label: const Text(
                'Hello',
                key: labelKey,
              ),
            ),
          ),
        ),
      ),
    );

    final Rect paddingRect = tester.getRect(find.byType(Padding));
    final Rect labelRect = tester.getRect(find.byKey(labelKey));
    final Rect iconRect = tester.getRect(find.byType(Icon));

    // The right padding should be applied on the right of the label, whereas the
    // left padding should be applied on the left side of the icon.
    expect(paddingRect.right, labelRect.right + 10);
    expect(paddingRect.left, iconRect.left - 16);
    // Use the taller widget to check the top and bottom padding.
    final Rect tallerWidget = iconRect.height > labelRect.height ? iconRect : labelRect;
    expect(paddingRect.top, tallerWidget.top - 5);
    expect(paddingRect.bottom, tallerWidget.bottom + 12);
  });

  group('Default ElevatedButton padding for textScaleFactor, textDirection', () {
    const ValueKey<String> buttonKey = ValueKey<String>('button');
    const ValueKey<String> labelKey = ValueKey<String>('label');
    const ValueKey<String> iconKey = ValueKey<String>('icon');

    const List<double> textScaleFactorOptions = <double>[0.5, 1.0, 1.25, 1.5, 2.0, 2.5, 3.0, 4.0];
    const List<TextDirection> textDirectionOptions = <TextDirection>[TextDirection.ltr, TextDirection.rtl];
    const List<Widget> iconOptions = <Widget>[null, Icon(Icons.add, size: 18, key: iconKey)];

    // Expected values for each textScaleFactor.
    final Map<double, double> paddingWithoutIconStart = <double, double>{
      0.5: 16,
      1: 16,
      1.25: 14,
      1.5: 12,
      2: 8,
      2.5: 6,
      3: 4,
      4: 4,
    };
    final Map<double, double> paddingWithoutIconEnd = <double, double>{
      0.5: 16,
      1: 16,
      1.25: 14,
      1.5: 12,
      2: 8,
      2.5: 6,
      3: 4,
      4: 4,
    };
    final Map<double, double> paddingWithIconStart = <double, double>{
      0.5: 12,
      1: 12,
      1.25: 11,
      1.5: 10,
      2: 8,
      2.5: 8,
      3: 8,
      4: 8,
    };
    final Map<double, double> paddingWithIconEnd = <double, double>{
      0.5: 16,
      1: 16,
      1.25: 14,
      1.5: 12,
      2: 8,
      2.5: 6,
      3: 4,
      4: 4,
    };
    final Map<double, double> paddingWithIconGap = <double, double>{
      0.5: 8,
      1: 8,
      1.25: 7,
      1.5: 6,
      2: 4,
      2.5: 4,
      3: 4,
      4: 4,
    };

    Rect globalBounds(RenderBox renderBox) {
      final Offset topLeft = renderBox.localToGlobal(Offset.zero);
      return topLeft & renderBox.size;
    }

    /// Computes the padding between two [Rect]s, one inside the other.
    EdgeInsets paddingBetween({ Rect parent, Rect child }) {
      assert (parent.intersect(child) == child);
      return EdgeInsets.fromLTRB(
        child.left - parent.left,
        child.top - parent.top,
        parent.right - child.right,
        parent.bottom - child.bottom,
      );
    }

    for (final double textScaleFactor in textScaleFactorOptions) {
      for (final TextDirection textDirection in textDirectionOptions) {
        for (final Widget icon in iconOptions) {
          final String testName = 'ElevatedButton'
            ', text scale $textScaleFactor'
            '${icon != null ? ", with icon" : ""}'
            '${textDirection == TextDirection.rtl ? ", RTL" : ""}';

          testWidgets(testName, (WidgetTester tester) async {
            await tester.pumpWidget(
              MaterialApp(
                theme: ThemeData.from(colorScheme: const ColorScheme.light()),
                home: Builder(
                  builder: (BuildContext context) {
                    return MediaQuery(
                      data: MediaQuery.of(context).copyWith(
                        textScaleFactor: textScaleFactor,
                      ),
                      child: Directionality(
                        textDirection: textDirection,
                        child: Scaffold(
                          body: Center(
                            child: icon == null
                              ? ElevatedButton(
                                  key: buttonKey,
                                  onPressed: () {},
                                  child: const Text('button', key: labelKey),
                                )
                              : ElevatedButton.icon(
                                  key: buttonKey,
                                  onPressed: () {},
                                  icon: icon,
                                  label: const Text('button', key: labelKey),
                                ),
                          ),
                        ),
                      ),
                    );
                  },
                ),
              ),
            );

            final Element paddingElement = tester.element(
              find.descendant(
                of: find.byKey(buttonKey),
                matching: find.byType(Padding),
              ),
            );
            expect(Directionality.of(paddingElement), textDirection);
            final Padding paddingWidget = paddingElement.widget as Padding;

            // Compute expected padding, and check.

            final double expectedStart = icon != null
              ? paddingWithIconStart[textScaleFactor]
              : paddingWithoutIconStart[textScaleFactor];
            final double expectedEnd = icon != null
              ? paddingWithIconEnd[textScaleFactor]
              : paddingWithoutIconEnd[textScaleFactor];
            final EdgeInsets expectedPadding = EdgeInsetsDirectional.fromSTEB(expectedStart, 0, expectedEnd, 0)
              .resolve(textDirection);

            expect(paddingWidget.padding.resolve(textDirection), expectedPadding);

            // Measure padding in terms of the difference between the button and its label child
            // and check that.

            final RenderBox labelRenderBox = tester.renderObject<RenderBox>(find.byKey(labelKey));
            final Rect labelBounds = globalBounds(labelRenderBox);
            final RenderBox iconRenderBox = icon == null ? null : tester.renderObject<RenderBox>(find.byKey(iconKey));
            final Rect iconBounds = icon == null ? null : globalBounds(iconRenderBox);
            final Rect childBounds = icon == null ? labelBounds : labelBounds.expandToInclude(iconBounds);

            // We measure the `InkResponse` descendant of the button
            // element, because the button has a larger `RenderBox`
            // which accommodates the minimum tap target with a height
            // of 48.
            final RenderBox buttonRenderBox = tester.renderObject<RenderBox>(
              find.descendant(
                of: find.byKey(buttonKey),
                matching: find.byWidgetPredicate(
                  (Widget widget) => widget is InkResponse,
                ),
              ),
            );
            final Rect buttonBounds = globalBounds(buttonRenderBox);
            final EdgeInsets visuallyMeasuredPadding = paddingBetween(
              parent: buttonBounds,
              child: childBounds,
            );

            // Since there is a requirement of a minimum width of 64
            // and a minimum height of 36 on material buttons, the visual
            // padding of smaller buttons may not match their settings.
            // Therefore, we only test buttons that are large enough.
            if (buttonBounds.width > 64) {
              expect(
                visuallyMeasuredPadding.left,
                expectedPadding.left,
              );
              expect(
                visuallyMeasuredPadding.right,
                expectedPadding.right,
              );
            }

            if (buttonBounds.height > 36) {
              expect(
                visuallyMeasuredPadding.top,
                expectedPadding.top,
              );
              expect(
                visuallyMeasuredPadding.bottom,
                expectedPadding.bottom,
              );
            }

            // Check the gap between the icon and the label
            if (icon != null) {
              final double gapWidth = textDirection == TextDirection.ltr
                ? labelBounds.left - iconBounds.right
                : iconBounds.left - labelBounds.right;
              expect(gapWidth, paddingWithIconGap[textScaleFactor]);
            }

            // Check the text's height - should be consistent with the textScaleFactor.
            final RenderBox textRenderObject = tester.renderObject<RenderBox>(
              find.descendant(
                of: find.byKey(labelKey),
                matching: find.byElementPredicate(
                  (Element element) => element.widget is RichText,
                ),
              ),
            );
            final double textHeight = textRenderObject.paintBounds.size.height;
            final double expectedTextHeight = 14 * textScaleFactor;
            expect(textHeight, moreOrLessEquals(expectedTextHeight, epsilon: 0.5));
          });
        }
      }
    }
  });

  testWidgets('Override ElevatedButton default padding', (WidgetTester tester) async {
    await tester.pumpWidget(
      MaterialApp(
        theme: ThemeData.from(colorScheme: const ColorScheme.light()),
        home: Builder(
          builder: (BuildContext context) {
            return MediaQuery(
              data: MediaQuery.of(context).copyWith(
                textScaleFactor: 2,
              ),
              child: Scaffold(
                body: Center(
                  child: ElevatedButton(
                    style: ElevatedButton.styleFrom(padding: const EdgeInsets.all(22)),
                    onPressed: () {},
                    child: const Text('ElevatedButton')
                  ),
                ),
              ),
            );
          },
        ),
      ),
    );

    final Padding paddingWidget = tester.widget<Padding>(
      find.descendant(
        of: find.byType(ElevatedButton),
        matching: find.byType(Padding),
      ),
    );
    expect(paddingWidget.padding, const EdgeInsets.all(22));
  });

  testWidgets('Elevated buttons animate elevation before color on disable', (WidgetTester tester) async {
    // This is a regression test for https://github.com/flutter/flutter/issues/387

    const ColorScheme colorScheme = ColorScheme.light();
    final Color backgroundColor = colorScheme.primary;
    final Color disabledBackgroundColor = colorScheme.onSurface.withOpacity(0.12);

    Widget buildFrame({ bool enabled }) {
      return MaterialApp(
        theme: ThemeData.from(colorScheme: colorScheme),
        home: Center(
          child: ElevatedButton(
            onPressed: enabled ? () { } : null,
            child: const Text('button'),
          ),
        ),
      );
    }

    PhysicalShape physicalShape() {
      return tester.widget<PhysicalShape>(
        find.descendant(
          of: find.byType(ElevatedButton),
          matching: find.byType(PhysicalShape),
        ),
      );
    }

    // Default elevation is 2, background color is primary.
    await tester.pumpWidget(buildFrame(enabled: true));
    expect(physicalShape().elevation, 2);
    expect(physicalShape().color, backgroundColor);

    // Disabled elevation animates to 0 over 200ms, THEN the background
    // color changes to onSurface.withOpacity(0.12)
    await tester.pumpWidget(buildFrame(enabled: false));
    await tester.pump(const Duration(milliseconds: 50));
    expect(physicalShape().elevation, lessThan(2));
    expect(physicalShape().color, backgroundColor);
    await tester.pump(const Duration(milliseconds: 150));
    expect(physicalShape().elevation, 0);
    expect(physicalShape().color, backgroundColor);
    await tester.pumpAndSettle();
    expect(physicalShape().elevation, 0);
    expect(physicalShape().color, disabledBackgroundColor);
  });
}

TextStyle _iconStyle(WidgetTester tester, IconData icon) {
  final RichText iconRichText = tester.widget<RichText>(
    find.descendant(of: find.byIcon(icon), matching: find.byType(RichText)),
  );
  return iconRichText.text.style;
}