Add tests for new effects

test/effects/box_shadow_test.dart

@@ -0,0 +1,35 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter_animate/flutter_animate.dart';
+
+import '../tester_extensions.dart';
+
+void main() {
+  testWidgets('BoxShadowEffect: core', (tester) async {
+    BoxShadow? begin;
+    BoxShadow end = const BoxShadow(blurRadius: 32, color: Colors.red);
+    BorderRadius borderRadius = BorderRadius.circular(8);
+
+    // uses a Placeholder instead of FlutterLogo because the latter apparently has its own DecoratedBox
+    final animation = const Placeholder().animate().boxShadow(
+          duration: 1000.ms,
+          borderRadius: borderRadius,
+          begin: begin,
+          end: end,
+        );
+
+    // Check middle:
+    await tester.pumpAnimation(animation, initialDelay: 500.ms);
+    var expected = BoxShadow.lerp(begin, end, 0.5);
+    tester.expectWidgetWithBool<DecoratedBox>(
+      (o) => (o.decoration as BoxDecoration).boxShadow?.first == expected,
+      true,
+      'decoration.boxShadow @ 500ms',
+    );
+    tester.expectWidgetWithBool<DecoratedBox>(
+      (o) => (o.decoration as BoxDecoration).borderRadius == borderRadius,
+      true,
+      'decoration.borderRadius @ 500ms',
+    );
+  });
+}

test/effects/color_test.dart

@@ -0,0 +1,35 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter_animate/flutter_animate.dart';
+
+import '../tester_extensions.dart';
+
+void main() {
+  testWidgets('ColorEffect: core', (tester) async {
+    BlendMode blend = BlendMode.colorDodge;
+    Color begin = Colors.blue, end = Colors.red;
+
+    final animation = const FlutterLogo().animate().color(
+          duration: 1000.ms,
+          blendMode: blend,
+          begin: begin,
+          end: end,
+        );
+
+    // Check begin:
+    await tester.pumpAnimation(animation);
+    tester.expectWidgetWithBool<ColorFiltered>(
+      (o) => o.colorFilter == ColorFilter.mode(begin, blend),
+      true,
+      'colorFilter @ 0ms',
+    );
+
+    // Check end:
+    await tester.pump(1000.ms);
+    tester.expectWidgetWithBool<ColorFiltered>(
+      (o) => o.colorFilter == ColorFilter.mode(end, blend),
+      true,
+      'colorFilter @ 1000ms',
+    );
+  });
+}

test/effects/crossfade_test.dart

@@ -0,0 +1,61 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter_animate/flutter_animate.dart';
+
+import '../tester_extensions.dart';
+
+void main() {
+  testWidgets('CrossfadeEffect: core', (tester) async {
+    Widget beginChild = const FlutterLogo(), endChild = const Placeholder();
+    final anim = beginChild.animate().crossfade(
+          duration: 1000.ms,
+          delay: 0.ms,
+          builder: (_) => endChild,
+        );
+
+    // At begin, expect beginChild is 100% opaque, endChild is 0%
+    await tester.pumpAnimation(anim);
+    tester.expectWidgetWithDouble<FadeTransition>(
+      (o) => o.opacity.value,
+      1,
+      'beginChild opacity @ 0ms',
+      findFirst: true,
+    );
+    tester.expectWidgetWithDouble<FadeTransition>(
+      (o) => o.opacity.value,
+      0,
+      'endChild opacity @ 0ms',
+      findFirst: false,
+    );
+
+    // At middle, expect beginChild is 50% opaque, endChild is 50%
+    await tester.pump(500.ms);
+    tester.expectWidgetWithDouble<FadeTransition>(
+      (o) => o.opacity.value,
+      0.5,
+      'beginChild opacity @ 500ms',
+      findFirst: true,
+    );
+    tester.expectWidgetWithDouble<FadeTransition>(
+      (o) => o.opacity.value,
+      0.5,
+      'endChild opacity @ 500ms',
+      findFirst: false,
+    );
+
+    // At end, expect beginChild is 0% opaque, endChild is 100%
+    await tester.pump(500.ms);
+    tester.expectWidgetWithDouble<FadeTransition>(
+      (o) => o.opacity.value,
+      0,
+      'beginChild opacity @ 1000ms',
+      findFirst: true,
+    );
+    tester.expectWidgetWithDouble<FadeTransition>(
+      (o) => o.opacity.value,
+      1,
+      'endChild opacity @ 1000ms',
+      findFirst: false,
+    );
+  });
+}

test/effects/elevation_test.dart

@@ -0,0 +1,27 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter_animate/flutter_animate.dart';
+
+import '../tester_extensions.dart';
+
+void main() {
+  testWidgets('ElevationEffect: core', (tester) async {
+    double begin = 4, end = 32;
+
+    final animation = const FlutterLogo().animate().elevation(
+          duration: 1000.ms,
+          begin: begin,
+          end: end,
+        );
+
+    // Check begin:
+    await tester.pumpAnimation(animation);
+    tester.expectWidgetWithBool<PhysicalModel>(
+        (o) => o.elevation == begin, true, 'elevation @ 0ms');
+
+    // Check end:
+    await tester.pump(1000.ms);
+    tester.expectWidgetWithBool<PhysicalModel>(
+        (o) => o.elevation == end, true, 'elevation @ 1000ms');
+  });
+}

test/effects/flip_test.dart

@@ -0,0 +1,3 @@
+void main() {
+  // TODO: expose FlipEffect.getTransformMatrix (name TBD) and use in test
+}

test/effects/swap_test.dart

@@ -7,7 +7,7 @@ import '../tester_extensions.dart';
 void main() {
   testWidgets('SwapEffect: core', (tester) async {
     final anim = const FlutterLogo().animate().fadeOut(duration: 500.ms).swap(
-          builder: (_, __) => const Placeholder().animate().fadeIn(),
+          builder: (_, __) => const Placeholder(),
         );
 
     await tester.pumpAnimation(anim);