[Material] Create theme for Dividers to enable customization of thickness (#38621)

packages/flutter/lib/material.dart

@@ -50,6 +50,7 @@ export 'src/material/debug.dart';
 export 'src/material/dialog.dart';
 export 'src/material/dialog_theme.dart';
 export 'src/material/divider.dart';
+export 'src/material/divider_theme.dart';
 export 'src/material/drawer.dart';
 export 'src/material/drawer_header.dart';
 export 'src/material/dropdown.dart';

packages/flutter/lib/src/material/divider.dart

@@ -5,18 +5,18 @@
 import 'package:flutter/widgets.dart';
 import 'package:flutter/painting.dart';
 
+import 'divider_theme.dart';
 import 'theme.dart';
 
 // Examples can assume:
 // BuildContext context;
 
-/// A one device pixel thick horizontal line, with padding on either
+/// A thin horizontal line, with padding on either side.
-/// side.
 ///
 /// In the material design language, this represents a divider. Dividers can be
 /// used in lists, [Drawer]s, and elsewhere to separate content.
 ///
-/// To create a one-pixel divider between [ListTile] items, consider using
+/// To create a divider between [ListTile] items, consider using
 /// [ListTile.divideTiles], which is optimized for this case.
 ///
 /// The box's total height is controlled by [height]. The appropriate
@@ -30,36 +30,56 @@ import 'theme.dart';
 class Divider extends StatelessWidget {
   /// Creates a material design divider.
   ///
-  /// The height must be positive.
+  /// The [height], [thickness], [indent], and [endIndent] must be null or
+  /// non-negative.
   const Divider({
     Key key,
-    this.height = 16.0,
+    this.height,
-    this.indent = 0.0,
+    this.thickness,
-    this.endIndent = 0.0,
+    this.indent,
+    this.endIndent,
     this.color,
-  }) : assert(height >= 0.0),
+  }) : assert(height == null || height >= 0.0),
+       assert(thickness == null || thickness >= 0.0),
+       assert(indent == null || indent >= 0.0),
+       assert(endIndent == null || endIndent >= 0.0),
        super(key: key);
 
 
   /// The divider's height extent.
   ///
-  /// The divider itself is always drawn as one device pixel thick horizontal
+  /// The divider itself is always drawn as a horizontal line that is centered
-  /// line that is centered within the height specified by this value.
+  /// within the height specified by this value.
   ///
-  /// A divider with a [height] of 0.0 is always drawn as a line with a height
+  /// If this is null, then the [DividerThemeData.space] is used. If that is
-  /// of exactly one device pixel, without any padding around it.
+  /// also null, then this defaults to 16.0.
   final double height;
 
-  /// The amount of empty space to the left of the divider.
+  /// The thickness of the line drawn within the divider.
+  ///
+  /// A divider with a [thickness] of 0.0 is always drawn as a line with a
+  /// height of exactly one device pixel.
+  ///
+  /// If this is null, then the [DividerThemeData.dividerThickness] is used. If
+  /// that is also null, then this defaults to 0.0.
+  final double thickness;
+
+  /// The amount of empty space to the leading edge of the divider.
+  ///
+  /// If this is null, then the [DividerThemeData.indent] is used. If that is
+  /// also null, then this defaults to 0.0.
   final double indent;
 
-  /// The amount of empty space to the right of the divider.
+  /// The amount of empty space to the trailing edge of the divider.
+  ///
+  /// If this is null, then the [DividerThemeData.endIndent] is used. If that is
+  /// also null, then this defaults to 0.0.
   final double endIndent;
 
   /// The color to use when painting the line.
   ///
-  /// Defaults to the current theme's divider color, given by
+  /// If this is null, then the [DividerThemeData.color] is used. If that is
-  /// [ThemeData.dividerColor].
+  /// also null, then [ThemeData.dividerColor] is used.
   ///
   /// {@tool sample}
   ///
@@ -76,7 +96,7 @@ class Divider extends StatelessWidget {
   /// [ThemeData.dividerColor] specified in the ambient [Theme].
   ///
   /// The `width` argument can be used to override the default width of the
-  /// divider border, which is usually 0.0 (a hairline border).
+  /// divider border, which defaults to 0.0 (a hairline border).
   ///
   /// {@tool sample}
   ///
@@ -96,25 +116,30 @@ class Divider extends StatelessWidget {
   /// )
   /// ```
   /// {@end-tool}
-  static BorderSide createBorderSide(BuildContext context, { Color color, double width = 0.0 }) {
+  static BorderSide createBorderSide(BuildContext context, { Color color, double width }) {
-    assert(width != null);
     return BorderSide(
-      color: color ?? Theme.of(context).dividerColor,
+      color: color ?? DividerTheme.of(context).color ?? Theme.of(context).dividerColor,
-      width: width,
+      width: width ?? DividerTheme.of(context).thickness ?? 0.0,
     );
   }
 
   @override
   Widget build(BuildContext context) {
+    final DividerThemeData dividerTheme = DividerTheme.of(context);
+    final double height = this.height ?? dividerTheme.space ?? 16.0;
+    final double thickness = this.thickness ?? dividerTheme.thickness ?? 0.0;
+    final double indent = this.indent ?? dividerTheme.indent ?? 0.0;
+    final double endIndent = this.endIndent ?? dividerTheme.endIndent ?? 0.0;
+
     return SizedBox(
       height: height,
       child: Center(
         child: Container(
-          height: 0.0,
+          height: thickness,
           margin: EdgeInsetsDirectional.only(start: indent, end: endIndent),
           decoration: BoxDecoration(
             border: Border(
-              bottom: createBorderSide(context, color: color),
+              bottom: createBorderSide(context, color: color, width: thickness),
             ),
           ),
         ),
@@ -123,8 +148,7 @@ class Divider extends StatelessWidget {
   }
 }
 
-/// A one device pixel thick vertical line, with padding on either
+/// A thin vertical line, with padding on either side.
-/// side.
 ///
 /// In the material design language, this represents a divider. Vertical
 /// dividers can be used in horizontally scrolling lists, such as a
@@ -138,37 +162,57 @@ class Divider extends StatelessWidget {
 ///  * [ListView.separated], which can be used to generate vertical dividers.
 ///  * <https://material.io/design/components/dividers.html>
 class VerticalDivider extends StatelessWidget {
-  /// Creates a material design divider.
+  /// Creates a material design vertical divider.
   ///
-  /// The width must be positive.
+  /// The [width], [thickness], [indent], and [endIndent] must be null or
+  /// non-negative.
   const VerticalDivider({
     Key key,
-    this.width = 16.0,
+    this.width,
-    this.indent = 0.0,
+    this.thickness,
-    this.endIndent = 0.0,
+    this.indent,
+    this.endIndent,
     this.color,
-  }) : assert(width >= 0.0),
+  }) : assert(width == null || width >= 0.0),
+       assert(thickness == null || thickness >= 0.0),
+       assert(indent == null || indent >= 0.0),
+       assert(endIndent == null || endIndent >= 0.0),
        super(key: key);
 
   /// The divider's width.
   ///
-  /// The divider itself is always drawn as one device pixel thick
+  /// The divider itself is always drawn as a vertical line that is centered
-  /// line that is centered within the width specified by this value.
+  /// within the width specified by this value.
   ///
-  /// A divider with a [width] of 0.0 is always drawn as a line with a width
+  /// If this is null, then the [DividerThemeData.space] is used. If that is
-  /// of exactly one device pixel, without any padding around it.
+  /// also null, then this defaults to 16.0.
   final double width;
 
+  /// The thickness of the line drawn within the divider.
+  ///
+  /// A divider with a [thickness] of 0.0 is always drawn as a line with a
+  /// width of exactly one device pixel.
+  ///
+  /// If this is null, then the [DividerThemeData.thickness] is used which
+  /// defaults to 0.0.
+  final double thickness;
+
   /// The amount of empty space on top of the divider.
+  ///
+  /// If this is null, then the [DividerThemeData.indent] is used. If that is
+  /// also null, then this defaults to 0.0.
   final double indent;
 
   /// The amount of empty space under the divider.
+  ///
+  /// If this is null, then the [DividerThemeData.endIndent] is used. If that is
+  /// also null, then this defaults to 0.0.
   final double endIndent;
 
   /// The color to use when painting the line.
   ///
-  /// Defaults to the current theme's divider color, given by
+  /// If this is null, then the [DividerThemeData.color] is used. If that is
-  /// [ThemeData.dividerColor].
+  /// also null, then [ThemeData.dividerColor] is used.
   ///
   /// {@tool sample}
   ///
@@ -182,15 +226,21 @@ class VerticalDivider extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
+    final DividerThemeData dividerTheme = DividerTheme.of(context);
+    final double width = this.width ?? dividerTheme.space ?? 16.0;
+    final double thickness = this.thickness ?? dividerTheme.thickness ?? 0.0;
+    final double indent = this.indent ?? dividerTheme.indent ?? 0.0;
+    final double endIndent = this.endIndent ?? dividerTheme.endIndent ?? 0.0;
+
     return SizedBox(
       width: width,
       child: Center(
         child: Container(
-          width: 0.0,
+          width: thickness,
           margin: EdgeInsetsDirectional.only(top: indent, bottom: endIndent),
           decoration: BoxDecoration(
             border: Border(
-              left: Divider.createBorderSide(context, color: color),
+              left: Divider.createBorderSide(context, color: color, width: thickness),
             ),
           ),
         ),

packages/flutter/lib/src/material/divider_theme.dart

@@ -0,0 +1,168 @@
+// 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 'dart:ui' show lerpDouble;
+
+import 'package:flutter/foundation.dart';
+import 'package:flutter/widgets.dart';
+
+import 'theme.dart';
+
+/// Defines the visual properties of [Divider], [VerticalDivider], dividers
+/// between [ListTile]s, and dividers between rows in [DataTable]s.
+///
+/// Descendant widgets obtain the current [DividerThemeData] object using
+/// `DividerTheme.of(context)`. Instances of [DividerThemeData]
+/// can be customized with [DividerThemeData.copyWith].
+///
+/// Typically a [DividerThemeData] is specified as part of the overall
+/// [Theme] with [ThemeData.dividerTheme].
+///
+/// All [DividerThemeData] properties are `null` by default. When null,
+/// the widgets will provide their own defaults.
+///
+/// See also:
+///
+///  * [ThemeData], which describes the overall theme information for the
+///    application.
+class DividerThemeData extends Diagnosticable {
+
+  /// Creates a theme that can be used for [DividerTheme] or
+  /// [ThemeData.dividerTheme].
+  const DividerThemeData({
+    this.color,
+    this.space,
+    this.thickness,
+    this.indent,
+    this.endIndent,
+  });
+
+  /// The color of [Divider]s and [VerticalDivider]s, also
+  /// used between [ListTile]s, between rows in [DataTable]s, and so forth.
+  final Color color;
+
+  /// The [Divider]'s width or the [VerticalDivider]'s height.
+  ///
+  /// This represents the amount of horizontal or vertical space the divider
+  /// takes up.
+  final double space;
+
+  /// The thickness of the line drawn within the divider.
+  final double thickness;
+
+  /// The amount of empty space at the leading edge of [Divider] or top edge of
+  /// [VerticalDivider].
+  final double indent;
+
+  /// The amount of empty space at the trailing edge of [Divider] or bottom edge
+  /// of [VerticalDivider].
+  final double endIndent;
+
+  /// Creates a copy of this object with the given fields replaced with the
+  /// new values.
+  DividerThemeData copyWith({
+    Color color,
+    double space,
+    double thickness,
+    double indent,
+    double endIndent,
+  }) {
+    return DividerThemeData(
+      color: color ?? this.color,
+      space: space ?? this.space,
+      thickness: thickness ?? this.thickness,
+      indent: indent ?? this.indent,
+      endIndent: endIndent ?? this.endIndent,
+    );
+  }
+
+  /// Linearly interpolate between two Divider themes.
+  ///
+  /// The argument `t` must not be null.
+  ///
+  /// {@macro dart.ui.shadow.lerp}
+  static DividerThemeData lerp(DividerThemeData a, DividerThemeData b, double t) {
+    assert(t != null);
+    return DividerThemeData(
+      color: Color.lerp(a?.color, b?.color, t),
+      space: lerpDouble(a?.space, b?.space, t),
+      thickness: lerpDouble(a?.thickness, b?.thickness, t),
+      indent: lerpDouble(a?.indent, b?.indent, t),
+      endIndent: lerpDouble(a?.endIndent, b?.endIndent, t),
+    );
+  }
+
+  @override
+  int get hashCode {
+    return hashValues(
+      color,
+      space,
+      thickness,
+      indent,
+      endIndent,
+    );
+  }
+
+  @override
+  bool operator ==(dynamic other) {
+    if (identical(this, other))
+      return true;
+    if (other.runtimeType != runtimeType)
+      return false;
+    final DividerThemeData typedOther = other;
+    return typedOther.color == color
+        && typedOther.space == space
+        && typedOther.thickness == thickness
+        && typedOther.indent == indent
+        && typedOther.endIndent == endIndent;
+  }
+
+  @override
+  void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+    super.debugFillProperties(properties);
+    properties.add(ColorProperty('color', color, defaultValue: null));
+    properties.add(DoubleProperty('space', space, defaultValue: null));
+    properties.add(DoubleProperty('thickness', thickness, defaultValue: null));
+    properties.add(DoubleProperty('indent', indent, defaultValue: null));
+    properties.add(DoubleProperty('endIndent', endIndent, defaultValue: null));
+  }
+}
+
+/// An inherited widget that defines the configuration for
+/// [Divider]s, [VerticalDividers]s, dividers between [ListTile]s, and dividers
+/// between rows in [DataTable]s in this widget's subtree.
+class DividerTheme extends InheritedWidget {
+  /// Creates a divider theme that controls the configurations for
+  /// [Divider]s, [VerticalDividers]s, dividers between [ListTile]s, and dividers
+  /// between rows in [DataTable]s in its widget subtree.
+  const DividerTheme({
+    Key key,
+    @required this.data,
+    Widget child,
+  }) : assert(data != null),
+       super(key: key, child: child);
+
+  /// The properties for descendant [Divider]s, [VerticalDividers]s, dividers
+  /// between [ListTile]s, and dividers between rows in [DataTable]s.
+  final DividerThemeData data;
+
+  /// The closest instance of this class's [data] value that encloses the given
+  /// context.
+  ///
+  /// If there is no ancestor, it returns [ThemeData.dividerTheme]. Applications
+  /// can assume that the returned value will not be null.
+  ///
+  /// Typical usage is as follows:
+  ///
+  /// ```dart
+  /// DividerThemeData theme = DividerTheme.of(context);
+  /// ```
+  static DividerThemeData of(BuildContext context) {
+    final DividerTheme dividerTheme = context.inheritFromWidgetOfExactType(DividerTheme);
+    return dividerTheme?.data ?? Theme.of(context).dividerTheme;
+  }
+
+  @override
+  bool updateShouldNotify(DividerTheme oldWidget) => data != oldWidget.data;
+}

packages/flutter/lib/src/material/theme_data.dart

@@ -19,6 +19,7 @@ import 'chip_theme.dart';
 import 'color_scheme.dart';
 import 'colors.dart';
 import 'dialog_theme.dart';
+import 'divider_theme.dart';
 import 'floating_action_button_theme.dart';
 import 'ink_splash.dart';
 import 'ink_well.dart' show InteractiveInkFeatureFactory;
@@ -178,6 +179,7 @@ class ThemeData extends Diagnosticable {
     BottomSheetThemeData bottomSheetTheme,
     PopupMenuThemeData popupMenuTheme,
     MaterialBannerThemeData bannerTheme,
+    DividerThemeData dividerTheme,
   }) {
     brightness ??= Brightness.light;
     final bool isDark = brightness == Brightness.dark;
@@ -282,6 +284,7 @@ class ThemeData extends Diagnosticable {
     bottomSheetTheme ??= const BottomSheetThemeData();
     popupMenuTheme ??= const PopupMenuThemeData();
     bannerTheme ??= const MaterialBannerThemeData();
+    dividerTheme ??= const DividerThemeData();
 
     return ThemeData.raw(
       brightness: brightness,
@@ -344,6 +347,7 @@ class ThemeData extends Diagnosticable {
       bottomSheetTheme: bottomSheetTheme,
       popupMenuTheme: popupMenuTheme,
       bannerTheme: bannerTheme,
+      dividerTheme: dividerTheme,
     );
   }
 
@@ -418,6 +422,7 @@ class ThemeData extends Diagnosticable {
     @required this.bottomSheetTheme,
     @required this.popupMenuTheme,
     @required this.bannerTheme,
+    @required this.dividerTheme,
   }) : assert(brightness != null),
        assert(primaryColor != null),
        assert(primaryColorBrightness != null),
@@ -474,7 +479,8 @@ class ThemeData extends Diagnosticable {
        assert(snackBarTheme != null),
        assert(bottomSheetTheme != null),
        assert(popupMenuTheme != null),
-       assert(bannerTheme != null);
+       assert(bannerTheme != null),
+       assert(dividerTheme != null);
 
   /// Create a [ThemeData] based on the colors in the given [colorScheme] and
   /// text styles of the optional [textTheme].
@@ -867,6 +873,10 @@ class ThemeData extends Diagnosticable {
   /// A theme for customizing the color and text style of a [MaterialBanner].
   final MaterialBannerThemeData bannerTheme;
 
+  /// A theme for customizing the color, thickness, and indents of [Divider]s,
+  /// [VerticalDivider]s, etc.
+  final DividerThemeData dividerTheme;
+
   /// Creates a copy of this theme but with the given fields replaced with the new values.
   ThemeData copyWith({
     Brightness brightness,
@@ -929,6 +939,7 @@ class ThemeData extends Diagnosticable {
     BottomSheetThemeData bottomSheetTheme,
     PopupMenuThemeData popupMenuTheme,
     MaterialBannerThemeData bannerTheme,
+    DividerThemeData dividerTheme,
   }) {
     cupertinoOverrideTheme = cupertinoOverrideTheme?.noDefault();
     return ThemeData.raw(
@@ -992,6 +1003,7 @@ class ThemeData extends Diagnosticable {
       bottomSheetTheme: bottomSheetTheme ?? this.bottomSheetTheme,
       popupMenuTheme: popupMenuTheme ?? this.popupMenuTheme,
       bannerTheme: bannerTheme ?? this.bannerTheme,
+      dividerTheme: dividerTheme ?? this.dividerTheme,
     );
   }
 
@@ -1133,6 +1145,7 @@ class ThemeData extends Diagnosticable {
       bottomSheetTheme: BottomSheetThemeData.lerp(a.bottomSheetTheme, b.bottomSheetTheme, t),
       popupMenuTheme: PopupMenuThemeData.lerp(a.popupMenuTheme, b.popupMenuTheme, t),
       bannerTheme: MaterialBannerThemeData.lerp(a.bannerTheme, b.bannerTheme, t),
+      dividerTheme: DividerThemeData.lerp(a.dividerTheme, b.dividerTheme, t),
     );
   }
 
@@ -1201,7 +1214,8 @@ class ThemeData extends Diagnosticable {
            (otherData.snackBarTheme == snackBarTheme) &&
            (otherData.bottomSheetTheme == bottomSheetTheme) &&
            (otherData.popupMenuTheme == popupMenuTheme) &&
-           (otherData.bannerTheme == bannerTheme);
+           (otherData.bannerTheme == bannerTheme) &&
+           (otherData.dividerTheme == dividerTheme);
   }
 
   @override
@@ -1270,6 +1284,7 @@ class ThemeData extends Diagnosticable {
       bottomSheetTheme,
       popupMenuTheme,
       bannerTheme,
+      dividerTheme,
     ];
     return hashList(values);
   }
@@ -1335,6 +1350,7 @@ class ThemeData extends Diagnosticable {
     properties.add(DiagnosticsProperty<BottomSheetThemeData>('bottomSheetTheme', bottomSheetTheme, defaultValue: defaultData.bottomSheetTheme));
     properties.add(DiagnosticsProperty<PopupMenuThemeData>('popupMenuTheme', popupMenuTheme, defaultValue: defaultData.popupMenuTheme));
     properties.add(DiagnosticsProperty<MaterialBannerThemeData>('bannerTheme', bannerTheme, defaultValue: defaultData.bannerTheme));
+    properties.add(DiagnosticsProperty<DividerThemeData>('dividerTheme', dividerTheme, defaultValue: defaultData.dividerTheme));
   }
 }
 

packages/flutter/test/material/divider_test.dart

@@ -19,7 +19,25 @@ void main() {
     );
     final RenderBox box = tester.firstRenderObject(find.byType(Divider));
     expect(box.size.height, 16.0);
-    expect(find.byType(Divider), paints..path(strokeWidth: 0.0));
+    final Container container = tester.widget(find.byType(Container));
+    final BoxDecoration decoration = container.decoration;
+    expect(decoration.border.bottom.width, 0.0);
+  });
+
+  testWidgets('Divider custom thickness', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      const Directionality(
+        textDirection: TextDirection.ltr,
+        child: Center(
+          child: Divider(
+            thickness: 5.0,
+          ),
+        ),
+      ),
+    );
+    final Container container = tester.widget(find.byType(Container));
+    final BoxDecoration decoration = container.decoration;
+    expect(decoration.border.bottom.width, 5.0);
   });
 
   testWidgets('Horizontal divider custom indentation', (WidgetTester tester) async {
@@ -86,7 +104,27 @@ void main() {
     );
     final RenderBox box = tester.firstRenderObject(find.byType(VerticalDivider));
     expect(box.size.width, 16.0);
-    expect(find.byType(VerticalDivider), paints..path(strokeWidth: 0.0));
+    final Container container = tester.widget(find.byType(Container));
+    final BoxDecoration decoration = container.decoration;
+    final Border border = decoration.border;
+    expect(border.left.width, 0.0);
+  });
+
+  testWidgets('Divider custom thickness', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      const Directionality(
+        textDirection: TextDirection.ltr,
+        child: Center(
+          child: VerticalDivider(
+            thickness: 5.0,
+          ),
+        ),
+      ),
+    );
+    final Container container = tester.widget(find.byType(Container));
+    final BoxDecoration decoration = container.decoration;
+    final Border border = decoration.border;
+    expect(border.left.width, 5.0);
   });
 
   testWidgets('Vertical Divider Test 2', (WidgetTester tester) async {

packages/flutter/test/material/divider_theme_test.dart

@@ -0,0 +1,238 @@
+// 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/rendering.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  test('DividerThemeData copyWith, ==, hashCode basics', () {
+    expect(const DividerThemeData(), const DividerThemeData().copyWith());
+    expect(const DividerThemeData().hashCode, const DividerThemeData().copyWith().hashCode);
+  });
+
+  test('DividerThemeData null fields by default', () {
+    const DividerThemeData dividerTheme = DividerThemeData();
+    expect(dividerTheme.color, null);
+    expect(dividerTheme.space, null);
+    expect(dividerTheme.thickness, null);
+    expect(dividerTheme.indent, null);
+    expect(dividerTheme.endIndent, null);
+  });
+
+  testWidgets('Default DividerThemeData debugFillProperties', (WidgetTester tester) async {
+    final DiagnosticPropertiesBuilder builder = DiagnosticPropertiesBuilder();
+    const DividerThemeData().debugFillProperties(builder);
+
+    final List<String> description = builder.properties
+        .where((DiagnosticsNode node) => !node.isFiltered(DiagnosticLevel.info))
+        .map((DiagnosticsNode node) => node.toString())
+        .toList();
+
+    expect(description, <String>[]);
+  });
+
+  testWidgets('DividerThemeData implements debugFillProperties', (WidgetTester tester) async {
+    final DiagnosticPropertiesBuilder builder = DiagnosticPropertiesBuilder();
+    const DividerThemeData(
+      color: Color(0xFFFFFFFF),
+      space: 5.0,
+      thickness: 4.0,
+      indent: 3.0,
+      endIndent: 2.0,
+    ).debugFillProperties(builder);
+
+    final List<String> description = builder.properties
+        .where((DiagnosticsNode node) => !node.isFiltered(DiagnosticLevel.info))
+        .map((DiagnosticsNode node) => node.toString())
+        .toList();
+
+    expect(description, <String>[
+      'color: Color(0xffffffff)',
+      'space: 5.0',
+      'thickness: 4.0',
+      'indent: 3.0',
+      'endIndent: 2.0',
+    ]);
+  });
+
+  group('Horizontal Divider', () {
+    testWidgets('Passing no DividerThemeData returns defaults', (WidgetTester tester) async {
+      await tester.pumpWidget(const MaterialApp(
+        home: Scaffold(
+          body: Divider(),
+        ),
+      ));
+
+      final RenderBox box = tester.firstRenderObject(find.byType(Divider));
+      expect(box.size.height, 16.0);
+
+      final Container container = tester.widget(find.byType(Container));
+      final BoxDecoration decoration = container.decoration;
+      expect(decoration.border.bottom.width, 0.0);
+
+      final ThemeData theme = ThemeData();
+      expect(decoration.border.bottom.color, theme.dividerColor);
+
+      final Rect dividerRect = tester.getRect(find.byType(Divider));
+      final Rect lineRect = tester.getRect(find.byType(DecoratedBox));
+      expect(lineRect.left, dividerRect.left);
+      expect(lineRect.right, dividerRect.right);
+    });
+
+    testWidgets('Uses values from DividerThemeData', (WidgetTester tester) async {
+      final DividerThemeData dividerTheme = _dividerTheme();
+      await tester.pumpWidget(MaterialApp(
+        theme: ThemeData(dividerTheme: dividerTheme),
+        home: const Scaffold(
+          body: Divider(),
+        ),
+      ));
+
+      final RenderBox box = tester.firstRenderObject(find.byType(Divider));
+      expect(box.size.height, dividerTheme.space);
+
+      final Container container = tester.widget(find.byType(Container));
+      final BoxDecoration decoration = container.decoration;
+      expect(decoration.border.bottom.width, dividerTheme.thickness);
+      expect(decoration.border.bottom.color, dividerTheme.color);
+
+      final Rect dividerRect = tester.getRect(find.byType(Divider));
+      final Rect lineRect = tester.getRect(find.byType(DecoratedBox));
+      expect(lineRect.left, dividerRect.left + dividerTheme.indent);
+      expect(lineRect.right, dividerRect.right - dividerTheme.endIndent);
+    });
+
+    testWidgets('Widget properties take priority over theme', (WidgetTester tester) async {
+      const Color color = Colors.purple;
+      const double height = 10.0;
+      const double thickness = 5.0;
+      const double indent = 8.0;
+      const double endIndent = 9.0;
+
+      final DividerThemeData dividerTheme = _dividerTheme();
+      await tester.pumpWidget(MaterialApp(
+        theme: ThemeData(dividerTheme: dividerTheme),
+        home: const Scaffold(
+          body: Divider(
+            color: color,
+            height: height,
+            thickness: thickness,
+            indent: indent,
+            endIndent: endIndent,
+          ),
+        ),
+      ));
+
+      final RenderBox box = tester.firstRenderObject(find.byType(Divider));
+      expect(box.size.height, height);
+
+      final Container container = tester.widget(find.byType(Container));
+      final BoxDecoration decoration = container.decoration;
+      expect(decoration.border.bottom.width, thickness);
+      expect(decoration.border.bottom.color, color);
+
+      final Rect dividerRect = tester.getRect(find.byType(Divider));
+      final Rect lineRect = tester.getRect(find.byType(DecoratedBox));
+      expect(lineRect.left, dividerRect.left + indent);
+      expect(lineRect.right, dividerRect.right - endIndent);
+    });
+  });
+
+  group('Vertical Divider', () {
+    testWidgets('Passing no DividerThemeData returns defaults', (WidgetTester tester) async {
+      await tester.pumpWidget(const MaterialApp(
+        home: Scaffold(
+          body: VerticalDivider(),
+        ),
+      ));
+
+      final RenderBox box = tester.firstRenderObject(find.byType(VerticalDivider));
+      expect(box.size.width, 16.0);
+
+      final Container container = tester.widget(find.byType(Container));
+      final BoxDecoration decoration = container.decoration;
+      final Border border = decoration.border;
+      expect(border.left.width, 0.0);
+
+      final ThemeData theme = ThemeData();
+      expect(border.left.color, theme.dividerColor);
+
+      final Rect dividerRect = tester.getRect(find.byType(VerticalDivider));
+      final Rect lineRect = tester.getRect(find.byType(DecoratedBox));
+      expect(lineRect.top, dividerRect.top);
+      expect(lineRect.bottom, dividerRect.bottom);
+    });
+
+    testWidgets('Uses values from DividerThemeData', (WidgetTester tester) async {
+      final DividerThemeData dividerTheme = _dividerTheme();
+      await tester.pumpWidget(MaterialApp(
+        theme: ThemeData(dividerTheme: dividerTheme),
+        home: const Scaffold(
+          body: VerticalDivider(),
+        ),
+      ));
+
+      final RenderBox box = tester.firstRenderObject(find.byType(VerticalDivider));
+      expect(box.size.width, dividerTheme.space);
+
+      final Container container = tester.widget(find.byType(Container));
+      final BoxDecoration decoration = container.decoration;
+      final Border border = decoration.border;
+      expect(border.left.width, dividerTheme.thickness);
+      expect(border.left.color, dividerTheme.color);
+
+      final Rect dividerRect = tester.getRect(find.byType(VerticalDivider));
+      final Rect lineRect = tester.getRect(find.byType(DecoratedBox));
+      expect(lineRect.top, dividerRect.top + dividerTheme.indent);
+      expect(lineRect.bottom, dividerRect.bottom - dividerTheme.endIndent);
+    });
+
+    testWidgets('Widget properties take priority over theme', (WidgetTester tester) async {
+      const Color color = Colors.purple;
+      const double width = 10.0;
+      const double thickness = 5.0;
+      const double indent = 8.0;
+      const double endIndent = 9.0;
+
+      final DividerThemeData dividerTheme = _dividerTheme();
+      await tester.pumpWidget(MaterialApp(
+        theme: ThemeData(dividerTheme: dividerTheme),
+        home: const Scaffold(
+          body: VerticalDivider(
+            color: color,
+            width: width,
+            thickness: thickness,
+            indent: indent,
+            endIndent: endIndent,
+          ),
+        ),
+      ));
+
+      final RenderBox box = tester.firstRenderObject(find.byType(VerticalDivider));
+      expect(box.size.width, width);
+
+      final Container container = tester.widget(find.byType(Container));
+      final BoxDecoration decoration = container.decoration;
+      final Border border = decoration.border;
+      expect(border.left.width, thickness);
+      expect(border.left.color, color);
+
+      final Rect dividerRect = tester.getRect(find.byType(VerticalDivider));
+      final Rect lineRect = tester.getRect(find.byType(DecoratedBox));
+      expect(lineRect.top, dividerRect.top + indent);
+      expect(lineRect.bottom, dividerRect.bottom - endIndent);
+    });
+  });
+}
+
+DividerThemeData _dividerTheme() {
+  return const DividerThemeData(
+    color: Colors.orange,
+    space: 12.0,
+    thickness: 2.0,
+    indent: 7.0,
+    endIndent: 5.0,
+  );
+}