Improve test coverage for gestures.dart (#4773)

This patch adds tests for some code paths we weren't hitting before and removes
some dead code that couldn't be tested because it was unreachable.

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

@@ -2,22 +2,18 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import "dart:math" as math;
-import "dart:typed_data";
+import 'dart:math' as math;
+import 'dart:typed_data';
 
+// TODO(abarth): Consider using vector_math.
 class _Vector {
-  _Vector(int size)
-  : _offset = 0, _length = size, _elements = new Float64List(size);
-
-  _Vector.fromValues(List<double> values)
-  : _offset = 0, _length = values.length, _elements = values;
+  _Vector(int size) : _offset = 0, _length = size, _elements = new Float64List(size);
 
   _Vector.fromVOL(List<double> values, int offset, int length)
-  : _offset = offset, _length = length, _elements = values;
+    : _offset = offset, _length = length, _elements = values;
 
   final int _offset;
 
-  int get length => _length;
   final int _length;
 
   final List<double> _elements;
@@ -35,26 +31,14 @@ class _Vector {
   }
 
   double norm() => math.sqrt(this * this);
-
-  @override
-  String toString() {
-    String result = "";
-    for (int i = 0; i < _length; i++) {
-      if (i > 0)
-        result += ", ";
-        result += this[i].toString();
-    }
-    return result;
-  }
 }
 
+// TODO(abarth): Consider using vector_math.
 class _Matrix {
   _Matrix(int rows, int cols)
-  : _rows = rows,
-    _columns = cols,
+  : _columns = cols,
     _elements = new Float64List(rows * cols);
 
-  final int _rows;
   final int _columns;
   final List<double> _elements;
 
@@ -68,21 +52,6 @@ class _Matrix {
     row * _columns,
     _columns
   );
-
-  @override
-  String toString() {
-    String result = "";
-    for (int i = 0; i < _rows; i++) {
-      if (i > 0)
-        result += "; ";
-      for (int j = 0; j < _columns; j++) {
-        if (j > 0)
-          result += ", ";
-        result += get(i, j).toString();
-      }
-    }
-    return result;
-  }
 }
 
 /// An nth degree polynomial fit to a dataset.

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

@@ -456,23 +456,18 @@ class DelayedMultiDragGestureRecognizer extends MultiDragGestureRecognizer<_Dela
   /// defaults to [kLongPressTimeout] to match [LongPressGestureRecognizer] but
   /// can be changed for specific behaviors.
   DelayedMultiDragGestureRecognizer({
-    Duration delay: kLongPressTimeout
-  }) : _delay = delay {
+    this.delay: kLongPressTimeout
+  }) {
     assert(delay != null);
   }
 
   /// The amount of time the pointer must remain in the same place for the drag
   /// to be recognized.
-  Duration get delay => _delay;
-  Duration _delay;
-  set delay(Duration value) {
-    assert(value != null);
-    _delay = value;
-  }
+  final Duration delay;
 
   @override
   _DelayedPointerState createNewPointerState(PointerDownEvent event) {
-    return new _DelayedPointerState(event.position, _delay);
+    return new _DelayedPointerState(event.position, delay);
   }
 
   @override

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

@@ -16,15 +16,6 @@ class _Estimate {
   final Duration time;
   final int degree;
   final double confidence;
-
-  @override
-  String toString() {
-    return 'Estimate(xCoefficients: $xCoefficients, '
-                    'yCoefficients: $yCoefficients, '
-                    'time: $time, '
-                    'degree: $degree, '
-                    'confidence: $confidence)';
-  }
 }
 
 abstract class _VelocityTrackerStrategy {
@@ -33,46 +24,20 @@ abstract class _VelocityTrackerStrategy {
   void clear();
 }
 
-enum _Weighting {
-  weightingNone,
-  weightingDelta,
-  weightingCentral,
-  weightingRecent
-}
-
 class _Movement {
   Duration eventTime = Duration.ZERO;
   Point position = Point.origin;
 }
 
-typedef double _WeightChooser(int index);
-
 class _LeastSquaresVelocityTrackerStrategy extends _VelocityTrackerStrategy {
   static const int kHistorySize = 20;
   static const int kHorizonMilliseconds = 100;
 
-  _LeastSquaresVelocityTrackerStrategy(this.degree, _Weighting weighting)
-    : _index = 0, _movements = new List<_Movement>(kHistorySize) {
-    switch (weighting) {
-      case _Weighting.weightingNone:
-        _chooseWeight = null;
-        break;
-      case _Weighting.weightingDelta:
-        _chooseWeight = _weightDelta;
-        break;
-      case _Weighting.weightingCentral:
-        _chooseWeight = _weightCentral;
-        break;
-      case _Weighting.weightingRecent:
-        _chooseWeight = _weightRecent;
-        break;
-    }
-  }
+  _LeastSquaresVelocityTrackerStrategy(this.degree);
 
   final int degree;
-  final List<_Movement> _movements;
-  _WeightChooser _chooseWeight;
-  int _index;
+  final List<_Movement> _movements = new List<_Movement>(kHistorySize);
+  int _index = 0;
 
   @override
   void addMovement(Duration timeStamp, Point position) {
@@ -104,7 +69,7 @@ class _LeastSquaresVelocityTrackerStrategy extends _VelocityTrackerStrategy {
       Point position = movement.position;
       x.add(position.x);
       y.add(position.y);
-      w.add(_chooseWeight != null ? _chooseWeight(index) : 1.0);
+      w.add(1.0);
       time.add(-age);
       index = (index == 0 ? kHistorySize : index) - 1;
 
@@ -153,54 +118,6 @@ class _LeastSquaresVelocityTrackerStrategy extends _VelocityTrackerStrategy {
     _index = -1;
   }
 
-  double _weightDelta(int index) {
-    // Weight points based on how much time elapsed between them and the next
-    // point so that points that "cover" a shorter time span are weighed less.
-    //   delta  0ms: 0.5
-    //   delta 10ms: 1.0
-    if (index == _index)
-      return 1.0;
-    int nextIndex = (index + 1) % kHistorySize;
-    int deltaMilliseconds = (_movements[nextIndex].eventTime - _movements[index].eventTime).inMilliseconds;
-    if (deltaMilliseconds < 0)
-      return 0.5;
-    if (deltaMilliseconds < 10)
-      return 0.5 + deltaMilliseconds * 0.05;
-    return 1.0;
-  }
-
-  double _weightCentral(int index) {
-    // Weight points based on their age, weighing very recent and very old
-    // points less.
-    //   age  0ms: 0.5
-    //   age 10ms: 1.0
-    //   age 50ms: 1.0
-    //   age 60ms: 0.5
-    int ageMilliseconds = (_movements[_index].eventTime - _movements[index].eventTime).inMilliseconds;
-    if (ageMilliseconds < 0)
-      return 0.5;
-    if (ageMilliseconds < 10)
-      return 0.5 + ageMilliseconds * 0.05;
-    if (ageMilliseconds < 50)
-      return 1.0;
-    if (ageMilliseconds < 60)
-      return 0.5 + (60 - ageMilliseconds) * 0.05;
-    return 0.5;
-  }
-
-  double _weightRecent(int index) {
-    // Weight points based on their age, weighing older points less.
-    //   age   0ms: 1.0
-    //   age  50ms: 1.0
-    //   age 100ms: 0.5
-    int ageMilliseconds = (_movements[_index].eventTime - _movements[index].eventTime).inMilliseconds;
-    if (ageMilliseconds < 50)
-      return 1.0;
-    if (ageMilliseconds < 100)
-      return 0.5 + (100 - ageMilliseconds) * 0.01;
-    return 0.5;
-  }
-
   _Movement _getMovement(int i) {
     _Movement result = _movements[i];
     if (result == null) {
@@ -310,6 +227,6 @@ class VelocityTracker {
   }
 
   static _VelocityTrackerStrategy _createStrategy() {
-    return new _LeastSquaresVelocityTrackerStrategy(2, _Weighting.weightingNone);
+    return new _LeastSquaresVelocityTrackerStrategy(2);
   }
 }

packages/flutter/test/gestures/scroll_test.dart → packages/flutter/test/gestures/drag_test.dart

@@ -128,4 +128,34 @@ void main() {
 
     drag.dispose();
   });
+
+  testGesture('Clamp max velocity', (GestureTester tester) {
+    HorizontalDragGestureRecognizer drag = new HorizontalDragGestureRecognizer();
+
+    Velocity velocity;
+    drag.onEnd = (DragEndDetails details) {
+      velocity = details.velocity;
+    };
+
+    TestPointer pointer = new TestPointer(5);
+    PointerDownEvent down = pointer.down(const Point(10.0, 25.0), timeStamp: const Duration(milliseconds: 10));
+    drag.addPointer(down);
+    tester.closeArena(5);
+    tester.route(down);
+    tester.route(pointer.move(const Point(20.0, 25.0), timeStamp: const Duration(milliseconds: 10)));
+    tester.route(pointer.move(const Point(30.0, 25.0), timeStamp: const Duration(milliseconds: 11)));
+    tester.route(pointer.move(const Point(40.0, 25.0), timeStamp: const Duration(milliseconds: 12)));
+    tester.route(pointer.move(const Point(50.0, 25.0), timeStamp: const Duration(milliseconds: 13)));
+    tester.route(pointer.move(const Point(60.0, 25.0), timeStamp: const Duration(milliseconds: 14)));
+    tester.route(pointer.move(const Point(70.0, 25.0), timeStamp: const Duration(milliseconds: 15)));
+    tester.route(pointer.move(const Point(80.0, 25.0), timeStamp: const Duration(milliseconds: 16)));
+    tester.route(pointer.move(const Point(90.0, 25.0), timeStamp: const Duration(milliseconds: 17)));
+    tester.route(pointer.move(const Point(100.0, 25.0), timeStamp: const Duration(milliseconds: 18)));
+    tester.route(pointer.move(const Point(110.0, 25.0), timeStamp: const Duration(milliseconds: 19)));
+    tester.route(pointer.move(const Point(120.0, 25.0), timeStamp: const Duration(milliseconds: 20)));
+    tester.route(pointer.up(timeStamp: const Duration(milliseconds: 20)));
+    expect(velocity.pixelsPerSecond.dx, inInclusiveRange(0.99 * kMaxFlingVelocity, kMaxFlingVelocity));
+
+    drag.dispose();
+  });
 }

packages/flutter/test/gestures/events_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_test/flutter_test.dart';
+import 'package:flutter/gestures.dart';
+
+import 'gesture_tester.dart';
+
+void main() {
+  setUp(ensureGestureBinding);
+
+  testGesture('toString control tests', (GestureTester tester) {
+    expect(new PointerDownEvent(), hasOneLineDescription);
+    expect(new PointerDownEvent().toStringFull(), hasOneLineDescription);
+  });
+
+  testGesture('nthMouseButton control tests', (GestureTester tester) {
+    expect(nthMouseButton(2), kSecondaryMouseButton);
+    expect(nthStylusButton(2), kSecondaryStylusButton);
+  });
+}

packages/flutter/test/gestures/gesture_binding_test.dart

@@ -77,6 +77,34 @@ void main() {
     expect(events[2].runtimeType, equals(PointerUpEvent));
   });
 
+  test('Synthetic move events', () {
+    mojo_bindings.Encoder encoder = new mojo_bindings.Encoder();
+
+    PointerPacket packet = new PointerPacket();
+    packet.pointers = <Pointer>[new Pointer(), new Pointer()];
+    packet.pointers[0]
+      ..type = PointerType.down
+      ..kind = PointerKind.touch
+      ..x = 1.0
+      ..y = 3.0;
+    packet.pointers[1]
+      ..type = PointerType.up
+      ..kind = PointerKind.touch
+      ..x = 10.0
+      ..y = 15.0;
+    packet.encode(encoder);
+
+    List<PointerEvent> events = <PointerEvent>[];
+    _binding.callback = (PointerEvent event) => events.add(event);
+
+    ui.window.onPointerPacket(encoder.message.buffer);
+    expect(events.length, 3);
+    expect(events[0].runtimeType, equals(PointerDownEvent));
+    expect(events[1].runtimeType, equals(PointerMoveEvent));
+    expect(events[1].delta, equals(const Offset(9.0, 12.0)));
+    expect(events[2].runtimeType, equals(PointerUpEvent));
+  });
+
   test('Pointer cancel events', () {
     mojo_bindings.Encoder encoder = new mojo_bindings.Encoder();
 

packages/flutter/test/gestures/velocity_tracker_test.dart

@@ -3,7 +3,7 @@
 // found in the LICENSE file.
 
 import 'package:flutter/gestures.dart';
-import 'package:test/test.dart';
+import 'package:flutter_test/flutter_test.dart';
 import 'velocity_tracker_data.dart';
 
 bool _withinTolerance(double actual, double expected) {
@@ -47,4 +47,14 @@ void main() {
       }
     }
   });
+
+  test('Velocity control test', () {
+    Velocity velocity1 = new Velocity(pixelsPerSecond: const Offset(7.0, 0.0));
+    Velocity velocity2 = new Velocity(pixelsPerSecond: const Offset(12.0, 0.0));
+    expect(velocity1, equals(new Velocity(pixelsPerSecond: new Offset(7.0, 0.0))));
+    expect(velocity1, isNot(equals(velocity2)));
+    expect(velocity2 - velocity1, equals(new Velocity(pixelsPerSecond: new Offset(5.0, 0.0))));
+    expect(velocity1.hashCode, isNot(equals(velocity2.hashCode)));
+    expect(velocity1, hasOneLineDescription);
+  });
 }

packages/flutter/test/widget/hit_testing_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_test/flutter_test.dart';
+import 'package:flutter/gestures.dart';
+import 'package:flutter/widgets.dart';
+
+void main() {
+  testWidgets('toString control test', (WidgetTester tester) async {
+    await tester.pumpWidget(new Center(child: new Text('Hello')));
+    HitTestResult result = tester.hitTestOnBinding(Point.origin);
+    expect(result, hasOneLineDescription);
+    expect(result.path.first, hasOneLineDescription);
+  });
+}