71 lines
2.8 KiB
Dart
71 lines
2.8 KiB
Dart
// Copyright 2014 The Flutter Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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import 'package:flutter/physics.dart';
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import 'package:flutter_test/flutter_test.dart';
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void main() {
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test('Friction simulation positive velocity', () {
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final friction = FrictionSimulation(0.135, 100.0, 100.0);
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expect(friction.x(0.0), moreOrLessEquals(100.0));
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expect(friction.dx(0.0), moreOrLessEquals(100.0));
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expect(friction.x(0.1), moreOrLessEquals(110.0, epsilon: 1.0));
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expect(friction.x(0.5), moreOrLessEquals(131.0, epsilon: 1.0));
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expect(friction.x(2.0), moreOrLessEquals(149.0, epsilon: 1.0));
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expect(friction.finalX, moreOrLessEquals(149.0, epsilon: 1.0));
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expect(friction.timeAtX(100.0), 0.0);
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expect(friction.timeAtX(friction.x(0.1)), moreOrLessEquals(0.1));
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expect(friction.timeAtX(friction.x(0.5)), moreOrLessEquals(0.5));
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expect(friction.timeAtX(friction.x(2.0)), moreOrLessEquals(2.0));
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expect(friction.timeAtX(-1.0), double.infinity);
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expect(friction.timeAtX(200.0), double.infinity);
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});
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test('Friction simulation negative velocity', () {
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final friction = FrictionSimulation(0.135, 100.0, -100.0);
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expect(friction.x(0.0), moreOrLessEquals(100.0));
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expect(friction.dx(0.0), moreOrLessEquals(-100.0));
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expect(friction.x(0.1), moreOrLessEquals(91.0, epsilon: 1.0));
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expect(friction.x(0.5), moreOrLessEquals(68.0, epsilon: 1.0));
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expect(friction.x(2.0), moreOrLessEquals(51.0, epsilon: 1.0));
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expect(friction.finalX, moreOrLessEquals(50, epsilon: 1.0));
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expect(friction.timeAtX(100.0), 0.0);
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expect(friction.timeAtX(friction.x(0.1)), moreOrLessEquals(0.1));
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expect(friction.timeAtX(friction.x(0.5)), moreOrLessEquals(0.5));
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expect(friction.timeAtX(friction.x(2.0)), moreOrLessEquals(2.0));
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expect(friction.timeAtX(101.0), double.infinity);
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expect(friction.timeAtX(40.0), double.infinity);
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});
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test('Friction simulation constant deceleration', () {
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final friction = FrictionSimulation(0.135, 100.0, -100.0, constantDeceleration: 100);
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expect(friction.x(0.0), moreOrLessEquals(100.0));
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expect(friction.dx(0.0), moreOrLessEquals(-100.0));
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expect(friction.x(0.1), moreOrLessEquals(91.0, epsilon: 1.0));
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expect(friction.x(0.5), moreOrLessEquals(80.0, epsilon: 1.0));
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expect(friction.x(2.0), moreOrLessEquals(80.0, epsilon: 1.0));
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expect(friction.finalX, moreOrLessEquals(80.0, epsilon: 1.0));
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expect(friction.timeAtX(100.0), 0.0);
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expect(friction.timeAtX(friction.x(0.1)), moreOrLessEquals(0.1));
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expect(friction.timeAtX(friction.x(0.2)), moreOrLessEquals(0.2));
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expect(friction.timeAtX(friction.x(0.3)), moreOrLessEquals(0.3));
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expect(friction.timeAtX(101.0), double.infinity);
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expect(friction.timeAtX(40.0), double.infinity);
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});
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}
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