Fix several minor bugs and add many tests (#7506)

* MultiTapGestureRecognizer previously would assert if there was no
   competition.
 * GestureArenaTeam would always select the first recongizer as the
   winner even if a later recognizer actually accepted the pointer
   sequence.
 * debugPrintStack would fail a type check if maxFrames was non-null.
 * FractionalOffset.lerp would throw a null-pointer exception if its
   second argument was null.

Also, add a number of tests for previously untested lines of code.

packages/flutter/lib/src/foundation/assertions.dart

@@ -339,7 +339,7 @@ class FlutterError extends AssertionError {
 void debugPrintStack({ String label, int maxFrames }) {
   if (label != null)
     debugPrint(label);
-  List<String> lines = StackTrace.current.toString().trimRight().split('\n');
+  Iterable<String> lines = StackTrace.current.toString().trimRight().split('\n');
   if (maxFrames != null)
     lines = lines.take(maxFrames);
   debugPrint(FlutterError.defaultStackFilter(lines).join('\n'));

packages/flutter/lib/src/gestures/converter.dart

@@ -49,6 +49,7 @@ class PointerEventConverter {
       final Point position = new Point(datum.physicalX, datum.physicalY) / devicePixelRatio;
       final Duration timeStamp = datum.timeStamp;
       final PointerDeviceKind kind = datum.kind;
+      assert(datum.change != null);
       switch (datum.change) {
         case ui.PointerChange.add:
           assert(!_pointers.containsKey(datum.device));
@@ -325,10 +326,6 @@ class PointerEventConverter {
             radiusMax: datum.radiusMax
           );
           break;
-        default:
-          // TODO(ianh): once https://github.com/flutter/flutter/issues/720 is
-          // done, add real support for PointerAddedEvent and PointerRemovedEvent
-          assert(false);
       }
     }
   }

packages/flutter/lib/src/gestures/multitap.dart

@@ -221,12 +221,6 @@ class DoubleTapGestureRecognizer extends GestureRecognizer {
   String toStringShort() => 'double tap';
 }
 
-
-enum _TapResolution {
-  tap,
-  cancel
-}
-
 /// TapGesture represents a full gesture resulting from a single tap sequence,
 /// as part of a [MultiTapGestureRecognizer]. Tap gestures are passive, meaning
 /// that they will not preempt any other arena member in play.
@@ -246,7 +240,7 @@ class _TapGesture extends _TapTracker {
     if (longTapDelay > Duration.ZERO) {
       _timer = new Timer(longTapDelay, () {
         _timer = null;
-        gestureRecognizer._handleLongTap(event.pointer, _lastPosition);
+        gestureRecognizer._dispatchLongTap(event.pointer, _lastPosition);
       });
     }
   }
@@ -289,7 +283,7 @@ class _TapGesture extends _TapTracker {
 
   void reject() {
     stopTrackingPointer(handleEvent);
-    gestureRecognizer._resolveTap(pointer, _TapResolution.cancel, null);
+    gestureRecognizer._dispatchCancel(pointer);
   }
 
   void cancel() {
@@ -303,9 +297,8 @@ class _TapGesture extends _TapTracker {
 
   void _check() {
     if (_wonArena && _finalPosition != null)
-      gestureRecognizer._resolveTap(pointer, _TapResolution.tap, _finalPosition);
+      gestureRecognizer._dispatchTap(pointer, _finalPosition);
   }
-
 }
 
 /// Recognizes taps on a per-pointer basis.
@@ -365,31 +358,33 @@ class MultiTapGestureRecognizer extends GestureRecognizer {
   @override
   void acceptGesture(int pointer) {
     assert(_gestureMap.containsKey(pointer));
-    _gestureMap[pointer]?.accept();
-    assert(!_gestureMap.containsKey(pointer));
+    _gestureMap[pointer].accept();
   }
 
   @override
   void rejectGesture(int pointer) {
     assert(_gestureMap.containsKey(pointer));
-    _gestureMap[pointer]?.reject();
+    _gestureMap[pointer].reject();
     assert(!_gestureMap.containsKey(pointer));
   }
 
-  void _resolveTap(int pointer, _TapResolution resolution, Point globalPosition) {
+  void _dispatchCancel(int pointer) {
+    assert(_gestureMap.containsKey(pointer));
     _gestureMap.remove(pointer);
-    if (resolution == _TapResolution.tap) {
-      if (onTapUp != null)
-        invokeCallback/*<Null>*/('onTapUp', () => onTapUp(pointer, new TapUpDetails(globalPosition: globalPosition))); // ignore: STRONG_MODE_INVALID_CAST_FUNCTION_EXPR, https://github.com/dart-lang/sdk/issues/27504
-      if (onTap != null)
-        invokeCallback/*<Null>*/('onTap', () => onTap(pointer)); // ignore: STRONG_MODE_INVALID_CAST_FUNCTION_EXPR, https://github.com/dart-lang/sdk/issues/27504
-    } else {
-      if (onTapCancel != null)
-        invokeCallback/*<Null>*/('onTapCancel', () => onTapCancel(pointer)); // ignore: STRONG_MODE_INVALID_CAST_FUNCTION_EXPR, https://github.com/dart-lang/sdk/issues/27504
-    }
+    if (onTapCancel != null)
+      invokeCallback/*<Null>*/('onTapCancel', () => onTapCancel(pointer)); // ignore: STRONG_MODE_INVALID_CAST_FUNCTION_EXPR, https://github.com/dart-lang/sdk/issues/27504
+  }
+
+  void _dispatchTap(int pointer, Point globalPosition) {
+    assert(_gestureMap.containsKey(pointer));
+    _gestureMap.remove(pointer);
+    if (onTapUp != null)
+      invokeCallback/*<Null>*/('onTapUp', () => onTapUp(pointer, new TapUpDetails(globalPosition: globalPosition))); // ignore: STRONG_MODE_INVALID_CAST_FUNCTION_EXPR, https://github.com/dart-lang/sdk/issues/27504
+    if (onTap != null)
+      invokeCallback/*<Null>*/('onTap', () => onTap(pointer)); // ignore: STRONG_MODE_INVALID_CAST_FUNCTION_EXPR, https://github.com/dart-lang/sdk/issues/27504
   }
 
-  void _handleLongTap(int pointer, Point lastPosition) {
+  void _dispatchLongTap(int pointer, Point lastPosition) {
     assert(_gestureMap.containsKey(pointer));
     if (onLongTapDown != null)
       invokeCallback/*<Null>*/('onLongTapDown', () => onLongTapDown(pointer, new TapDownDetails(globalPosition: lastPosition))); // ignore: STRONG_MODE_INVALID_CAST_FUNCTION_EXPR, https://github.com/dart-lang/sdk/issues/27504
@@ -397,7 +392,7 @@ class MultiTapGestureRecognizer extends GestureRecognizer {
 
   @override
   void dispose() {
-    List<_TapGesture> localGestures = new List<_TapGesture>.from(_gestureMap.values);
+    final List<_TapGesture> localGestures = new List<_TapGesture>.from(_gestureMap.values);
     for (_TapGesture gesture in localGestures)
       gesture.cancel();
     // Rejection of each gesture should cause it to be removed from our map

packages/flutter/lib/src/gestures/team.dart

@@ -33,9 +33,11 @@ class _CombiningGestureArenaMember extends GestureArenaMember {
     assert(_pointer == pointer);
     assert(_winner != null || _members.isNotEmpty);
     _close();
-    _winner ??= _members.removeAt(0);
-    for (GestureArenaMember member in _members)
-      member.rejectGesture(pointer);
+    _winner ??= _members[0];
+    for (GestureArenaMember member in _members) {
+      if (member != _winner)
+        member.rejectGesture(pointer);
+    }
     _winner.acceptGesture(pointer);
   }
 
@@ -72,7 +74,7 @@ class _CombiningGestureArenaMember extends GestureArenaMember {
         _entry.resolve(disposition);
     } else {
       assert(disposition == GestureDisposition.accepted);
-      _winner ?? member;
+      _winner ??= member;
       _entry.resolve(disposition);
     }
   }

packages/flutter/lib/src/painting/fractional_offset.dart

@@ -141,7 +141,7 @@ class FractionalOffset {
     if (a == null)
       return new FractionalOffset(b.dx * t, b.dy * t);
     if (b == null)
-      return new FractionalOffset(b.dx * (1.0 - t), b.dy * (1.0 - t));
+      return new FractionalOffset(a.dx * (1.0 - t), a.dy * (1.0 - t));
     return new FractionalOffset(ui.lerpDouble(a.dx, b.dx, t), ui.lerpDouble(a.dy, b.dy, t));
   }
 

packages/flutter/test/animation/animations_test.dart

@@ -112,4 +112,40 @@ void main() {
     expect(animation, hasOneLineDescription);
     expect(animation.toString(), contains('no next'));
   });
+
+
+  test('AnimationMean control test', () {
+    AnimationController left = new AnimationController(
+      value: 0.5,
+      vsync: const TestVSync(),
+    );
+    AnimationController right = new AnimationController(
+      vsync: const TestVSync(),
+    );
+
+    AnimationMean mean = new AnimationMean(left: left, right: right);
+
+    expect(mean, hasOneLineDescription);
+    expect(mean.value, equals(0.25));
+
+    List<double> log = <double>[];
+    void logValue() {
+      log.add(mean.value);
+    }
+
+    mean.addListener(logValue);
+
+    right.value = 1.0;
+
+    expect(mean.value, equals(0.75));
+    expect(log, equals(<double>[0.75]));
+    log.clear();
+
+    mean.removeListener(logValue);
+
+    left.value = 0.0;
+
+    expect(mean.value, equals(0.50));
+    expect(log, isEmpty);
+  });
 }

packages/flutter/test/animation/tween_test.dart

@@ -41,4 +41,12 @@ void main() {
     expect(tween.lerp(0.5), 7);
     expect(tween.lerp(0.7), 8);
   });
+
+  test('RectTween', () {
+    Rect a = new Rect.fromLTWH(5.0, 3.0, 7.0, 11.0);
+    Rect b = new Rect.fromLTWH(8.0, 12.0, 14.0, 18.0);
+    RectTween tween = new RectTween(begin: a, end: b);
+    expect(tween.lerp(0.5), equals(Rect.lerp(a, b, 0.5)));
+    expect(tween, hasOneLineDescription);
+  });
 }

packages/flutter/test/foundation/assertions_test.dart

+// 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/foundation.dart';
+import 'package:test/test.dart';
+
+import 'capture_output.dart';
+
+void main() {
+  test('debugPrintStack', () {
+    final List<String> log = captureOutput(() {
+      debugPrintStack(label: 'Example label', maxFrames: 7);
+    });
+    expect(log[0], contains('Example label'));
+    expect(log[1], contains('debugPrintStack'));
+  });
+
+
+  test('debugPrintStack', () {
+    final List<String> log = captureOutput(() {
+      final FlutterErrorDetails details = new FlutterErrorDetails(
+        exception: 'Example exception',
+        stack: StackTrace.current,
+        library: 'Example library',
+        context: 'Example context',
+        informationCollector: (StringBuffer information) {
+          information.writeln('Example information');
+        },
+      );
+
+      FlutterError.dumpErrorToConsole(details);
+    });
+
+    expect(log[0], contains('EXAMPLE LIBRARY'));
+    expect(log[1], contains('Example context'));
+    expect(log[2], contains('Example exception'));
+
+    final String joined = log.join('\n');
+
+    expect(joined, contains('captureOutput'));
+    expect(joined, contains('\nExample information\n'));
+  });
+
+}

packages/flutter/test/foundation/bit_field_test.dart

+// 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/foundation.dart';
+import 'package:test/test.dart';
+
+enum _TestEnum {
+  a, b, c, d, e, f, g, h,
+}
+
+void main() {
+  test('BitField control test', () {
+    BitField<_TestEnum> field = new BitField<_TestEnum>(8);
+
+    expect(field[_TestEnum.d], isFalse);
+
+    field[_TestEnum.d] = true;
+    field[_TestEnum.e] = true;
+
+    expect(field[_TestEnum.c], isFalse);
+    expect(field[_TestEnum.d], isTrue);
+    expect(field[_TestEnum.e], isTrue);
+
+    field[_TestEnum.e] = false;
+
+    expect(field[_TestEnum.c], isFalse);
+    expect(field[_TestEnum.d], isTrue);
+    expect(field[_TestEnum.e], isFalse);
+
+    field.reset();
+
+    expect(field[_TestEnum.c], isFalse);
+    expect(field[_TestEnum.d], isFalse);
+    expect(field[_TestEnum.e], isFalse);
+
+    field.reset(true);
+
+    expect(field[_TestEnum.c], isTrue);
+    expect(field[_TestEnum.d], isTrue);
+    expect(field[_TestEnum.e], isTrue);
+  });
+
+  test('BitField.filed control test', () {
+    BitField<_TestEnum> field1 = new BitField<_TestEnum>.filled(8, true);
+
+    expect(field1[_TestEnum.d], isTrue);
+
+    BitField<_TestEnum> field2 = new BitField<_TestEnum>.filled(8, false);
+
+    expect(field2[_TestEnum.d], isFalse);
+  });
+}

packages/flutter/test/foundation/caching_iterable_test.dart

@@ -72,4 +72,22 @@ void main() {
     expect(integers, equals(<int>[1, 2, 3, 4, 5]));
     expect(yieldCount, equals(5));
   });
+
+  test('The Caching Iterable: take and skip', () {
+    Iterable<int> integers = new CachingIterable<int>(range(1, 5).iterator);
+    expect(yieldCount, equals(0));
+
+    Iterable<int> secondTwo = integers.skip(1).take(2);
+
+    expect(yieldCount, equals(0));
+    expect(secondTwo, equals(<int>[2, 3]));
+    expect(yieldCount, equals(3));
+
+    Iterable<int> result = integers.takeWhile((int i) => i < 4).skipWhile((int i) => i < 3);
+
+    expect(result, equals(<int>[3]));
+    expect(yieldCount, equals(4));
+    expect(integers, equals(<int>[1, 2, 3, 4, 5]));
+    expect(yieldCount, equals(5));
+  });
 }

packages/flutter/test/foundation/capture_output.dart

+// 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 'dart:async';
+import 'dart:ui' show VoidCallback;
+
+List<String> captureOutput(VoidCallback fn) {
+  List<String> log = <String>[];
+
+  runZoned(fn, zoneSpecification: new ZoneSpecification(
+    print: (Zone self,
+            ZoneDelegate parent,
+            Zone zone,
+            String line) {
+              log.add(line);
+            },
+  ));
+
+  return log;
+}

packages/flutter/test/foundation/change_notifier_test.dart

@@ -84,7 +84,7 @@ void main() {
     log.clear();
   });
 
-  testWidgets('ChangeNotifier with mutating listener', (WidgetTester tester) async {
+  test('ChangeNotifier with mutating listener', () {
     final TestNotifier test = new TestNotifier();
     final List<String> log = <String>[];
 
@@ -114,7 +114,7 @@ void main() {
     log.clear();
   });
 
-  testWidgets('Merging change notifiers', (WidgetTester tester) async {
+  test('Merging change notifiers', () {
     final TestNotifier source1 = new TestNotifier();
     final TestNotifier source2 = new TestNotifier();
     final TestNotifier source3 = new TestNotifier();
@@ -147,7 +147,7 @@ void main() {
     log.clear();
   });
 
-  testWidgets('Merging change notifiers ignores null', (WidgetTester tester) async {
+  test('Merging change notifiers ignores null', () {
     final TestNotifier source1 = new TestNotifier();
     final TestNotifier source2 = new TestNotifier();
     final List<String> log = <String>[];
@@ -161,4 +161,24 @@ void main() {
     expect(log, <String>['listener', 'listener']);
     log.clear();
   });
+
+  test('Can dispose merged notifier', () {
+    final TestNotifier source1 = new TestNotifier();
+    final TestNotifier source2 = new TestNotifier();
+    final List<String> log = <String>[];
+
+    final ChangeNotifier merged = new Listenable.merge(<Listenable>[source1, source2]);
+    final VoidCallback listener = () { log.add('listener'); };
+
+    merged.addListener(listener);
+    source1.notify();
+    source2.notify();
+    expect(log, <String>['listener', 'listener']);
+    log.clear();
+    merged.dispose();
+
+    source1.notify();
+    source2.notify();
+    expect(log, isEmpty);
+  });
 }

packages/flutter/test/foundation/print_test.dart

@@ -2,26 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'dart:async';
-
 import 'package:flutter/foundation.dart';
 import 'package:quiver/testing/async.dart';
 import 'package:test/test.dart';
 
-List<String> captureOutput(VoidCallback fn) {
-  List<String> log = <String>[];
-
-  runZoned(fn, zoneSpecification: new ZoneSpecification(
-    print: (Zone self,
-            ZoneDelegate parent,
-            Zone zone,
-            String line) {
-              log.add(line);
-            },
-  ));
-
-  return log;
-}
+import 'capture_output.dart';
 
 void main() {
   test('debugPrint', () {

packages/flutter/test/gestures/multidrag_test.dart

@@ -13,7 +13,7 @@ class TestDrag extends Drag {
 void main() {
   setUp(ensureGestureBinding);
 
-  testGesture('Should recognize pan', (GestureTester tester) {
+  testGesture('MultiDrag control test', (GestureTester tester) {
     DelayedMultiDragGestureRecognizer drag = new DelayedMultiDragGestureRecognizer();
 
     bool didStartDrag = false;

packages/flutter/test/gestures/multitap_test.dart

+// 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_test/flutter_test.dart';
+import 'package:flutter/gestures.dart';
+
+import 'gesture_tester.dart';
+
+class TestDrag extends Drag {
+}
+
+void main() {
+  setUp(ensureGestureBinding);
+
+  testGesture('Should recognize pan', (GestureTester tester) {
+    MultiTapGestureRecognizer tap = new MultiTapGestureRecognizer(longTapDelay: kLongPressTimeout);
+
+    List<String> log = <String>[];
+
+    tap.onTapDown = (int pointer, TapDownDetails details) { log.add('tap-down $pointer'); };
+    tap.onTapUp = (int pointer, TapUpDetails details) { log.add('tap-up $pointer'); };
+    tap.onTap = (int pointer) { log.add('tap $pointer'); };
+    tap.onLongTapDown = (int pointer, TapDownDetails details) { log.add('long-tap-down $pointer'); };
+    tap.onTapCancel = (int pointer) { log.add('tap-cancel $pointer'); };
+
+
+    TestPointer pointer5 = new TestPointer(5);
+    PointerDownEvent down5 = pointer5.down(const Point(10.0, 10.0));
+    tap.addPointer(down5);
+    tester.closeArena(5);
+    expect(log, <String>['tap-down 5']);
+    log.clear();
+    tester.route(down5);
+    expect(log, isEmpty);
+
+    TestPointer pointer6 = new TestPointer(6);
+    PointerDownEvent down6 = pointer6.down(const Point(15.0, 15.0));
+    tap.addPointer(down6);
+    tester.closeArena(6);
+    expect(log, <String>['tap-down 6']);
+    log.clear();
+    tester.route(down6);
+    expect(log, isEmpty);
+
+    tester.route(pointer5.move(const Point(11.0, 12.0)));
+    expect(log, isEmpty);
+
+    tester.route(pointer6.move(const Point(14.0, 13.0)));
+    expect(log, isEmpty);
+
+    tester.route(pointer5.up());
+    expect(log, <String>[
+      'tap-up 5',
+      'tap 5',
+    ]);
+    log.clear();
+
+    tester.async.elapse(kLongPressTimeout + kPressTimeout);
+    expect(log, <String>['long-tap-down 6']);
+    log.clear();
+
+    tester.route(pointer6.move(const Point(4.0, 3.0)));
+    expect(log, <String>['tap-cancel 6']);
+    log.clear();
+
+    tester.route(pointer6.up());
+    expect(log, isEmpty);
+
+    tap.dispose();
+  });
+}

packages/flutter/test/gestures/team_test.dart

+// 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_test/flutter_test.dart';
+import 'package:flutter/gestures.dart';
+
+import 'gesture_tester.dart';
+
+void main() {
+  setUp(ensureGestureBinding);
+
+  testGesture('GestureArenaTeam rejection test', (GestureTester tester) {
+
+    GestureArenaTeam team = new GestureArenaTeam();
+    HorizontalDragGestureRecognizer horizontalDrag = new HorizontalDragGestureRecognizer()..team = team;
+    VerticalDragGestureRecognizer verticalDrag = new VerticalDragGestureRecognizer()..team = team;
+    TapGestureRecognizer tap = new TapGestureRecognizer();
+
+    expect(horizontalDrag.team, equals(team));
+    expect(verticalDrag.team, equals(team));
+    expect(tap.team, isNull);
+
+    List<String> log = <String>[];
+
+    horizontalDrag.onStart = (DragStartDetails details) { log.add('hoizontal-drag-start'); };
+    verticalDrag.onStart = (DragStartDetails details) { log.add('vertical-drag-start'); };
+    tap.onTap = () { log.add('tap'); };
+
+    void test(Offset delta) {
+      Point origin = const Point(10.0, 10.0);
+      TestPointer pointer = new TestPointer(5);
+      PointerDownEvent down = pointer.down(origin);
+      horizontalDrag.addPointer(down);
+      verticalDrag.addPointer(down);
+      tap.addPointer(down);
+      expect(log, isEmpty);
+      tester.closeArena(5);
+      expect(log, isEmpty);
+      tester.route(down);
+      expect(log, isEmpty);
+      tester.route(pointer.move(origin + delta));
+      tester.route(pointer.up());
+    }
+
+    test(Offset.zero);
+    expect(log, <String>['tap']);
+    log.clear();
+
+    test(const Offset(0.0, 30.0));
+    expect(log, <String>['vertical-drag-start']);
+    log.clear();
+
+    horizontalDrag.dispose();
+    verticalDrag.dispose();
+    tap.dispose();
+  });
+}

packages/flutter/test/painting/edge_insets_test.dart

@@ -20,6 +20,9 @@ void main() {
     expect(insets.collapsedSize, const Size(16.0, 20.0));
     expect(insets.flipped, const EdgeInsets.fromLTRB(11.0, 13.0, 5.0, 7.0));
 
+    expect(insets.along(Axis.horizontal), equals(16.0));
+    expect(insets.along(Axis.vertical), equals(20.0));
+
     expect(insets.inflateRect(new Rect.fromLTRB(23.0, 32.0, 124.0, 143.0)),
            new Rect.fromLTRB(18.0, 25.0, 135.0, 156.0));
 
@@ -42,5 +45,9 @@ void main() {
     expect(EdgeInsets.lerp(a, b, 0.25), equals(b * 0.625));
     expect(EdgeInsets.lerp(a, b, 0.25), equals(a + const EdgeInsets.all(2.5)));
     expect(EdgeInsets.lerp(a, b, 0.25), equals(b - const EdgeInsets.all(7.5)));
+
+    expect(EdgeInsets.lerp(null, null, 0.25), isNull);
+    expect(EdgeInsets.lerp(null, b, 0.25), equals(b * 0.25));
+    expect(EdgeInsets.lerp(a, null, 0.25), equals(a * 0.75));
   });
 }

packages/flutter/test/painting/fractional_offset_test.dart

+// Copyright 2015 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/painting.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  test('FractionalOffset control test', () {
+    const FractionalOffset offset = const FractionalOffset(0.5, 0.25);
+
+    expect(offset, hasOneLineDescription);
+    expect(offset.hashCode, equals(new FractionalOffset(0.5, 0.25).hashCode));
+
+    expect(offset / 2.0, const FractionalOffset(0.25, 0.125));
+    expect(offset ~/ 2.0, const FractionalOffset(0.0, 0.0));
+    expect(offset % 5.0, const FractionalOffset(0.5, 0.25));
+  });
+
+  test('FractionalOffset.lerp()', () {
+    FractionalOffset a = FractionalOffset.topLeft;
+    FractionalOffset b = FractionalOffset.topCenter;
+    expect(FractionalOffset.lerp(a, b, 0.25), equals(new FractionalOffset(0.125, 0.0)));
+
+    expect(FractionalOffset.lerp(null, null, 0.25), isNull);
+    expect(FractionalOffset.lerp(null, b, 0.25), equals(b * 0.25));
+    expect(FractionalOffset.lerp(a, null, 0.25), equals(a * 0.75));
+  });
+}

packages/flutter/test/physics/clamped_simulation_test.dart

+// 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/physics.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  test('Clamped simulation', () {
+    GravitySimulation gravity = new GravitySimulation(9.81, 10.0, 0.0, 0.0);
+    ClampedSimulation clamped = new ClampedSimulation(gravity, xMin: 20.0, xMax: 100.0, dxMin: 7.0, dxMax: 11.0);
+
+    expect(clamped.x(0.0), equals(20.0));
+    expect(clamped.dx(0.0), equals(7.0));
+
+    expect(clamped.x(100.0), equals(100.0));
+    expect(clamped.dx(100.0), equals(11.0));
+  });
+}

packages/flutter/test/physics/newton_test.dart

@@ -70,6 +70,20 @@ void main() {
     expect(friction.dx(1.0), closeTo(endVelocity, epsilon));
   });
 
+  test('BoundedFrictionSimulation control test', () {
+    BoundedFrictionSimulation friction = new BoundedFrictionSimulation(0.3, 100.0, 400.0, 50.0, 150.0);
+
+    friction.tolerance = const Tolerance(velocity: 1.0);
+
+    expect(friction.isDone(0.0), false);
+    expect(friction.x(0.0), 100);
+    expect(friction.dx(0.0), 400.0);
+
+    expect(friction.x(1.0), equals(150.0));
+
+    expect(friction.isDone(1.0), true);
+  });
+
   test('test_gravity', () {
     GravitySimulation gravity = new GravitySimulation(200.0, 100.0, 600.0, 0.0);
 

packages/flutter/test/physics/tolerance_test.dart

+// 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/physics.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  test('Tolerance control test', () {
+    expect(Tolerance.defaultTolerance, hasOneLineDescription);
+  });
+}

packages/flutter/test/scheduler/debug_test.dart

+// Copyright 2015 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/scheduler.dart';
+import 'package:test/test.dart';
+
+void main() {
+  test('debugAssertAllSchedulerVarsUnset control test', () {
+    expect(() {
+      debugAssertAllSchedulerVarsUnset('Example test');
+    }, isNot(throws));
+
+    debugPrintBeginFrameBanner = true;
+
+    expect(() {
+      debugAssertAllSchedulerVarsUnset('Example test');
+    }, throws);
+
+    debugPrintBeginFrameBanner = false;
+    debugPrintEndFrameBanner = true;
+
+    expect(() {
+      debugAssertAllSchedulerVarsUnset('Example test');
+    }, throws);
+
+    debugPrintEndFrameBanner = false;
+
+    expect(() {
+      debugAssertAllSchedulerVarsUnset('Example test');
+    }, isNot(throws));
+  });
+}

packages/flutter/test/scheduler/ticker_test.dart

@@ -66,4 +66,17 @@ void main() {
     expect(ticker.isTicking, isFalse);
     expect(ticker.isActive, isFalse);
   });
+
+  testWidgets('Ticker control test', (WidgetTester tester) async {
+    Ticker ticker;
+
+    void testFunction() {
+      ticker = new Ticker(null);
+    }
+
+    testFunction();
+
+    expect(ticker, hasOneLineDescription);
+    expect(ticker.toString(debugIncludeStack: true), contains('testFunction'));
+  });
 }

packages/flutter/test/widgets/animated_size_test.dart

@@ -24,10 +24,10 @@ void main() {
           vsync: tester,
           child: const SizedBox(
             width: 100.0,
-            height: 100.0
-          )
-        )
-      )
+            height: 100.0,
+          ),
+        ),
+      ),
     );
 
     RenderBox box = tester.renderObject(find.byType(AnimatedSize));
@@ -41,10 +41,10 @@ void main() {
           vsync: tester,
           child: const SizedBox(
             width: 200.0,
-            height: 200.0
-          )
-        )
-      )
+            height: 200.0,
+          ),
+        ),
+      ),
     );
 
     await tester.pump(const Duration(milliseconds: 100));
@@ -68,10 +68,10 @@ void main() {
           vsync: tester,
           child: const SizedBox(
             width: 100.0,
-            height: 100.0
-          )
-        )
-      )
+            height: 100.0,
+          ),
+        ),
+      ),
     );
 
     await tester.pump(const Duration(milliseconds: 100));
@@ -100,11 +100,11 @@ void main() {
             vsync: tester,
             child: const SizedBox(
               width: 100.0,
-              height: 100.0
-            )
-          )
-        )
-      )
+              height: 100.0,
+            ),
+          ),
+        ),
+      ),
     );
 
     RenderBox box = tester.renderObject(find.byType(AnimatedSize));
@@ -121,11 +121,11 @@ void main() {
             vsync: tester,
             child: const SizedBox(
               width: 200.0,
-              height: 200.0
-            )
-          )
-        )
-      )
+              height: 200.0,
+            ),
+          ),
+        ),
+      ),
     );
 
     await tester.pump(const Duration(milliseconds: 100));
@@ -143,10 +143,10 @@ void main() {
           child: new AnimatedContainer(
             duration: const Duration(milliseconds: 100),
             width: 100.0,
-            height: 100.0
-          )
-        )
-      )
+            height: 100.0,
+          ),
+        ),
+      ),
     );
 
     RenderBox box = tester.renderObject(find.byType(AnimatedSize));
@@ -161,10 +161,10 @@ void main() {
           child: new AnimatedContainer(
             duration: const Duration(milliseconds: 100),
             width: 200.0,
-            height: 200.0
-          )
-        )
-      )
+            height: 200.0,
+          ),
+        ),
+      ),
     );
 
     await tester.pump(const Duration(milliseconds: 1)); // register change
@@ -176,4 +176,37 @@ void main() {
     expect(box.size.width, equals(200.0));
     expect(box.size.height, equals(200.0));
   });
+
+  testWidgets('AnimatedSize resync', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      new Center(
+        child: new AnimatedSize(
+          duration: const Duration(milliseconds: 200),
+          vsync: const TestVSync(),
+          child: new SizedBox(
+            width: 100.0,
+            height: 100.0,
+          ),
+        ),
+      ),
+    );
+
+    await tester.pumpWidget(
+      new Center(
+        child: new AnimatedSize(
+          duration: const Duration(milliseconds: 200),
+          vsync: tester,
+          child: new SizedBox(
+            width: 200.0,
+            height: 100.0,
+          ),
+        ),
+      ),
+    );
+
+    await tester.pump(const Duration(milliseconds: 100));
+
+    RenderBox box = tester.renderObject(find.byType(AnimatedSize));
+    expect(box.size.width, equals(150.0));
+  });
 }