examples/api/test/widgets/implicit_animations/animated_fractionally_sized_box.0_test.dart

// Copyright 2014 The Flutter 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:ui';

import 'package:flutter/material.dart';
import 'package:flutter_api_samples/widgets/implicit_animations/animated_fractionally_sized_box.0.dart'
    as example;
import 'package:flutter_test/flutter_test.dart';

void main() {
  testWidgets(
    'AnimatedFractionallySizedBox animates on tap',
    (WidgetTester tester) async {
      await tester.pumpWidget(
        const example.AnimatedFractionallySizedBoxExampleApp(),
      );

      final Finder fractionallySizedBoxFinder = find.descendant(
        of: find.byType(AnimatedFractionallySizedBox),
        matching: find.byType(FractionallySizedBox),
      );

      const double beginWidthFactor = 0.75;
      const double endWidthFactor = 0.25;
      const double beginHeightFactor = 0.25;
      const double endHeightFactor = 0.75;
      const Alignment beginAlignment = Alignment.bottomRight;
      const Alignment endAlignment = Alignment.topLeft;

      FractionallySizedBox fractionallySizedBox = tester.widget(
        fractionallySizedBoxFinder,
      );
      expect(fractionallySizedBox.widthFactor, beginWidthFactor);
      expect(fractionallySizedBox.heightFactor, beginHeightFactor);
      expect(fractionallySizedBox.alignment, beginAlignment);

      // Tap on the AnimatedFractionallySizedBoxExample to start the forward
      // animation.
      await tester.tap(
        find.byType(example.AnimatedFractionallySizedBoxExample),
      );
      await tester.pump();

      fractionallySizedBox = tester.widget(fractionallySizedBoxFinder);
      expect(fractionallySizedBox.widthFactor, beginWidthFactor);
      expect(fractionallySizedBox.heightFactor, beginHeightFactor);
      expect(fractionallySizedBox.alignment, beginAlignment);

      // Advance animation to the middle.
      await tester.pump(
        example.AnimatedFractionallySizedBoxExampleApp.duration ~/ 2,
      );

      final double t =
          example.AnimatedFractionallySizedBoxExampleApp.curve.transform(0.5);

      fractionallySizedBox = tester.widget(fractionallySizedBoxFinder);
      expect(
        fractionallySizedBox.widthFactor,
        lerpDouble(beginWidthFactor, endWidthFactor, t),
      );
      expect(
        fractionallySizedBox.heightFactor,
        lerpDouble(beginHeightFactor, endHeightFactor, t),
      );
      expect(
        fractionallySizedBox.alignment,
        Alignment.lerp(beginAlignment, endAlignment, t),
      );

      // Advance animation to the end.
      await tester.pump(
        example.AnimatedFractionallySizedBoxExampleApp.duration ~/ 2,
      );

      fractionallySizedBox = tester.widget(fractionallySizedBoxFinder);
      expect(fractionallySizedBox.widthFactor, endWidthFactor);
      expect(fractionallySizedBox.heightFactor, endHeightFactor);
      expect(fractionallySizedBox.alignment, endAlignment);

      // Tap on the AnimatedFractionallySizedBoxExample again to start the
      // reverse animation.
      await tester.tap(
        find.byType(example.AnimatedFractionallySizedBoxExample),
      );
      await tester.pump();

      fractionallySizedBox = tester.widget(fractionallySizedBoxFinder);
      expect(fractionallySizedBox.widthFactor, endWidthFactor);
      expect(fractionallySizedBox.heightFactor, endHeightFactor);
      expect(fractionallySizedBox.alignment, endAlignment);

      // Advance animation to the middle.
      await tester.pump(
        example.AnimatedFractionallySizedBoxExampleApp.duration ~/ 2,
      );

      fractionallySizedBox = tester.widget(fractionallySizedBoxFinder);
      expect(
        fractionallySizedBox.widthFactor,
        lerpDouble(endWidthFactor, beginWidthFactor, t),
      );
      expect(
        fractionallySizedBox.heightFactor,
        lerpDouble(endHeightFactor, beginHeightFactor, t),
      );
      expect(
        fractionallySizedBox.alignment,
        Alignment.lerp(endAlignment, beginAlignment, t),
      );

      // Advance animation to the end.
      await tester.pump(
        example.AnimatedFractionallySizedBoxExampleApp.duration ~/ 2,
      );

      fractionallySizedBox = tester.widget(fractionallySizedBoxFinder);
      expect(fractionallySizedBox.widthFactor, beginWidthFactor);
      expect(fractionallySizedBox.heightFactor, beginHeightFactor);
      expect(fractionallySizedBox.alignment, beginAlignment);
    },
  );
}