Fill in the test for rounded rectangle splash and highlights (#9092)

Fixes https://github.com/flutter/flutter/issues/9031

Also some updates to mock_canvas that were needed to do this.

packages/flutter/test/material/ink_paint_test.dart

@@ -0,0 +1,53 @@
+// Copyright 2017 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';
+
+import '../rendering/mock_canvas.dart';
+
+void main() {
+  testWidgets('Does the ink widget render a border radius', (WidgetTester tester) async {
+    final Color highlightColor = new Color(0xAAFF0000);
+    final Color splashColor = new Color(0xAA0000FF);
+    final BorderRadius borderRadius = new BorderRadius.circular(6.0);
+
+    await tester.pumpWidget(
+      new Material(
+        child: new Center(
+          child: new Container(
+            width: 200.0,
+            height: 60.0,
+            child: new InkWell(
+              borderRadius: borderRadius,
+              highlightColor: highlightColor,
+              splashColor: splashColor,
+              onTap: () { },
+            ),
+          ),
+        ),
+      ),
+    );
+
+    final Point center = tester.getCenter(find.byType(InkWell));
+    final TestGesture gesture = await tester.startGesture(center);
+    await tester.pump(); // start gesture
+    await tester.pump(new Duration(milliseconds: 200)); // wait for splash to be well under way
+
+    final RenderBox box = tester.renderObject<RenderPhysicalModel>(find.byType(PhysicalModel)).child;
+    expect(
+      box,
+      paints
+        ..clipRRect(rrect: new RRect.fromLTRBR(300.0, 270.0, 500.0, 330.0, new Radius.circular(6.0)))
+        ..circle(x: 400.0, y: 300.0, radius: 21.0, color: splashColor)
+        ..rrect(
+          rrect: new RRect.fromLTRBR(300.0, 270.0, 500.0, 330.0, new Radius.circular(6.0)),
+          color: highlightColor,
+        )
+    );
+
+    await gesture.up();
+  });
+}

packages/flutter/test/rendering/mock_canvas.dart

@@ -111,7 +111,7 @@ abstract class PaintPattern {
   /// See also: [save], [restore].
   void saveRestore();
 
-  /// Indicates that a rectangular clip.
+  /// Indicates that a rectangular clip is expected next.
   ///
   /// The next rectangular clip is examined. Any arguments that are passed to
   /// this method are compared to the actual [Canvas.clipRect] call's argument
@@ -135,6 +135,18 @@ abstract class PaintPattern {
   /// [Canvas.drawRect] call are ignored.
   void rect({ Rect rect, Color color });
 
+  /// Indicates that a rounded rectangle clip is expected next.
+  ///
+  /// The next rounded rectangle clip is examined. Any arguments that are passed
+  /// to this method are compared to the actual [Canvas.clipRRect] call's
+  /// argument and any mismatches result in failure.
+  ///
+  /// If no call to [Canvas.clipRRect] was made, then this results in failure.
+  ///
+  /// Any calls made between the last matched call (if any) and the
+  /// [Canvas.clipRRect] call are ignored.
+  void clipRRect({ RRect rrect });
+
   /// Indicates that a rounded rectangle is expected next.
   ///
   /// The next rounded rectangle is examined. Any arguments that are passed to
@@ -262,6 +274,11 @@ class _TestRecordingCanvasPatternMatcher extends Matcher implements PaintPattern
     _predicates.add(new _RectPaintPredicate(rect: rect, color: color, hasMaskFilter: hasMaskFilter, style: style));
   }
 
+  @override
+  void clipRRect({ RRect rrect }) {
+    _predicates.add(new _FunctionPaintPredicate(#clipRRect, <dynamic>[rrect]));
+  }
+
   @override
   void rrect({ RRect rrect, Color color, bool hasMaskFilter, PaintingStyle style }) {
     _predicates.add(new _RRectPaintPredicate(rrect: rrect, color: color, hasMaskFilter: hasMaskFilter, style: style));
@@ -331,6 +348,8 @@ class _TestRecordingCanvasPatternMatcher extends Matcher implements PaintPattern
 
   @override
   Description describe(Description description) {
+    if (_predicates.isEmpty)
+      return description.add('An object or closure and a paint pattern.');
     description.add('Object or closure painting: ');
     return description.addAll(
       '', ', ', '',
@@ -351,8 +370,13 @@ class _TestRecordingCanvasPatternMatcher extends Matcher implements PaintPattern
   bool _evaluatePredicates(Iterable<Invocation> calls, StringBuffer description) {
     // If we ever want to have a matcher for painting nothing, create a separate
     // paintsNothing matcher.
-    if (_predicates.isEmpty)
+    if (_predicates.isEmpty) {
-      throw new Exception('You must add a pattern to the paints matcher.');
+      description.write(
+        'painted something, but you must now add a pattern to the paints matcher '
+        'in the test to verify that it matches the important parts of the following.'
+      );
+      return false;
+    }
     if (calls.isEmpty) {
       description.write('painted nothing.');
       return false;

packages/flutter/test/widgets/ink_test.dart

@@ -1,41 +0,0 @@
-import 'package:flutter/material.dart';
-import 'package:flutter_test/flutter_test.dart';
-import 'package:flutter_test/src/widget_tester.dart';
-
-void main() {
-  testWidgets('Does the ink widget render a border radius', (WidgetTester tester) async {
-    final Color highlightColor = new Color(0xAAFF0000);
-    final Color splashColor = new Color(0xAA0000FF);
-
-    final Key materialKey = new UniqueKey();
-    final Key inkKey = new UniqueKey();
-    final BorderRadius borderRadius = new BorderRadius.circular(6.0);
-
-    await tester.pumpWidget(
-      new Material(
-        key: materialKey,
-        child: new Center(
-          child: new Container(
-            width: 200.0,
-            height: 60.0,
-            child: new InkWell(
-              key: inkKey,
-              borderRadius: borderRadius,
-              highlightColor: highlightColor,
-              splashColor: splashColor,
-              onTap: () {},
-            ),
-          ),
-        ),
-      ),
-    );
-
-    final Point center = tester.getCenter(find.byKey(materialKey));
-    final TestGesture gesture = await tester.startGesture(center);
-    await tester.pump(new Duration(milliseconds: 200));
-
-    // TODO(ianh) - stub. needs to be completed.
-
-    await gesture.up();
-  });
-}