129 lines
4.3 KiB
Dart
129 lines
4.3 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('When snapToEnd is set, value is exactly `end` after completion', () {
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final description = SpringDescription.withDampingRatio(mass: 1.0, stiffness: 400);
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const time = 0.4;
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final regularSimulation = SpringSimulation(
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description,
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0,
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1,
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0,
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tolerance: const Tolerance(distance: 0.1, velocity: 0.1),
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);
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expect(regularSimulation.x(time), lessThan(1));
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expect(regularSimulation.dx(time), greaterThan(0));
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final snappingSimulation = SpringSimulation(
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description,
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0,
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1,
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0,
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snapToEnd: true,
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tolerance: const Tolerance(distance: 0.1, velocity: 0.1),
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);
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// Must be exactly equal
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expect(snappingSimulation.x(time), 1);
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expect(snappingSimulation.dx(time), 0);
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});
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test('SpringSimulation results are continuous near critical damping', () {
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// Regression test for https://github.com/flutter/flutter/issues/163858
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const time = 0.4;
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const stiffness = 0.4;
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const mass = 0.4;
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final critical = SpringSimulation(
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SpringDescription.withDampingRatio(stiffness: stiffness, mass: mass),
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0,
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1,
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0,
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);
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expect(critical.x(time), moreOrLessEquals(0.06155, epsilon: 0.01));
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expect(critical.dx(time), moreOrLessEquals(0.2681, epsilon: 0.01));
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final slightlyOver = SpringSimulation(
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SpringDescription.withDampingRatio(stiffness: stiffness, mass: mass, ratio: 1 + 1e-3),
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0,
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1,
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0,
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);
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expect(slightlyOver.x(time), moreOrLessEquals(0.06155, epsilon: 0.01));
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expect(slightlyOver.dx(time), moreOrLessEquals(0.2681, epsilon: 0.01));
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final slightlyUnder = SpringSimulation(
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SpringDescription.withDampingRatio(stiffness: stiffness, mass: mass, ratio: 1 - 1e-3),
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0,
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1,
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0,
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);
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expect(slightlyUnder.x(time), moreOrLessEquals(0.06155, epsilon: 0.01));
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expect(slightlyUnder.dx(time), moreOrLessEquals(0.2681, epsilon: 0.01));
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});
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group('SpringDescription.withDurationAndBounce', () {
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test('creates spring with expected results', () {
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final spring = SpringDescription.withDurationAndBounce(bounce: 0.3);
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expect(spring.mass, equals(1.0));
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expect(spring.stiffness, moreOrLessEquals(157.91, epsilon: 0.01));
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expect(spring.damping, moreOrLessEquals(17.59, epsilon: 0.01));
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// Verify that getters recalculate correctly
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expect(spring.bounce, moreOrLessEquals(0.3, epsilon: 0.0001));
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expect(spring.duration.inMilliseconds, equals(500));
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});
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test('creates spring with negative bounce', () {
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final spring = SpringDescription.withDurationAndBounce(bounce: -0.3);
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expect(spring.mass, equals(1.0));
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expect(spring.stiffness, moreOrLessEquals(157.91, epsilon: 0.01));
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expect(spring.damping, moreOrLessEquals(35.90, epsilon: 0.01));
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// Verify that getters recalculate correctly
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expect(spring.bounce, moreOrLessEquals(-0.3, epsilon: 0.0001));
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expect(spring.duration.inMilliseconds, equals(500));
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});
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test('get duration and bounce based on mass and stiffness', () {
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const spring = SpringDescription(mass: 1.0, stiffness: 157.91, damping: 17.59);
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expect(spring.bounce, moreOrLessEquals(0.3, epsilon: 0.001));
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expect(spring.duration.inMilliseconds, equals(500));
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});
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test('custom duration', () {
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final spring = SpringDescription.withDurationAndBounce(
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duration: const Duration(milliseconds: 100),
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);
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expect(spring.mass, equals(1.0));
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expect(spring.stiffness, moreOrLessEquals(3947.84, epsilon: 0.01));
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expect(spring.damping, moreOrLessEquals(125.66, epsilon: 0.01));
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expect(spring.bounce, moreOrLessEquals(0, epsilon: 0.001));
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expect(spring.duration.inMilliseconds, equals(100));
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});
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test('duration <= 0 should fail', () {
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expect(
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() => SpringDescription.withDurationAndBounce(
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duration: const Duration(seconds: -1),
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bounce: 0.3,
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),
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throwsA(isAssertionError),
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);
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expect(
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() => SpringDescription.withDurationAndBounce(duration: Duration.zero, bounce: 0.3),
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throwsA(isAssertionError),
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);
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});
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});
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}
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