SpotiFLAC-Mobile/test/app_motion_test.dart

import 'package:flutter/material.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:material_3_expressive/material_3_expressive.dart';
import 'package:spotiflac_android/theme/app_motion.dart';
import 'package:spotiflac_android/theme/app_theme.dart';
import 'package:spotiflac_android/theme/mornye_theme.dart';

void main() {
  test('spring curves start at rest and settle within their duration', () {
    for (final spring in [
      M3EMotion.expressiveSpatialFast,
      M3EMotion.expressiveSpatialDefault,
      M3EMotion.expressiveSpatialSlow,
      M3EMotion.effectsFast,
      M3EMotion.effectsDefault,
    ]) {
      final curve = SpringCurve(spring);
      expect(curve.transform(0), 0);
      expect(curve.transform(1), 1);
      expect(curve.transform(0.98), closeTo(1, 0.01));
      expect(curve.duration.inMilliseconds, inInclusiveRange(100, 1200));
    }
  });

  test('spatial springs overshoot while effects springs do not', () {
    double peak(SpringCurve curve) => [
      for (var t = 0.0; t <= 1; t += 0.01) curve.transform(t),
    ].reduce((a, b) => a > b ? a : b);

    expect(
      peak(SpringCurve(M3EMotion.expressiveSpatialDefault)),
      greaterThan(1),
    );
    expect(peak(SpringCurve(M3EMotion.effectsDefault)), lessThanOrEqualTo(1));
  });

  Future<AppMotionSpec> resolve(
    WidgetTester tester, {
    required ThemeData theme,
    bool reduceMotion = false,
  }) async {
    late AppMotionSpec spec;
    await tester.pumpWidget(
      MaterialApp(
        theme: theme,
        home: MediaQuery(
          data: MediaQueryData(disableAnimations: reduceMotion),
          child: Builder(
            builder: (context) {
              spec = AppMotion.spatial(
                context,
                const AppMotionSpec(
                  Duration(milliseconds: 250),
                  Curves.easeOutCubic,
                ),
              );
              return const SizedBox();
            },
          ),
        ),
      ),
    );
    // MaterialApp animates theme changes between pumps.
    await tester.pumpAndSettle();
    return spec;
  }

  testWidgets(
    'Material uses springs; Mornye and reduced motion keep fallback',
    (tester) async {
      expect(
        (await resolve(tester, theme: AppTheme.light())).curve,
        isA<SpringCurve>(),
      );
      for (final spec in [
        await resolve(tester, theme: MornyeTheme.build(Brightness.light)),
        await resolve(tester, theme: AppTheme.light(), reduceMotion: true),
      ]) {
        expect(spec.curve, Curves.easeOutCubic);
        expect(spec.duration, const Duration(milliseconds: 250));
      }
    },
  );
}