From d12098da8aae83ade6a760fc9a70a47965b3928f Mon Sep 17 00:00:00 2001
From: houyushan <houyushan@oppo.com>
Date: Thu, 10 Dec 2020 06:48:03 +0800
Subject: [PATCH] Fix a ConstantTween's clerical error and Add some Tween
 testcases. (#71830)

---
 packages/flutter/lib/src/animation/tween.dart |  2 +-
 .../flutter/test/animation/tween_test.dart    | 30 +++++++++++++++++++
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/packages/flutter/lib/src/animation/tween.dart b/packages/flutter/lib/src/animation/tween.dart
index 865423b078..64bf3d3169 100644
--- a/packages/flutter/lib/src/animation/tween.dart
+++ b/packages/flutter/lib/src/animation/tween.dart
@@ -436,7 +436,7 @@ class ConstantTween<T> extends Tween<T> {
   T lerp(double t) => begin as T;
 
   @override
-  String toString() => '${objectRuntimeType(this, 'ReverseTween')}(value: $begin)';
+  String toString() => '${objectRuntimeType(this, 'ConstantTween')}(value: $begin)';
 }
 
 /// Transforms the value of the given animation by the given curve.
diff --git a/packages/flutter/test/animation/tween_test.dart b/packages/flutter/test/animation/tween_test.dart
index 71565febb4..94cbed3176 100644
--- a/packages/flutter/test/animation/tween_test.dart
+++ b/packages/flutter/test/animation/tween_test.dart
@@ -93,4 +93,34 @@ void main() {
     expect(tween.lerp(0.5), 100.0);
     expect(tween.lerp(1.0), 100.0);
   });
+
+  test('ReverseTween', () {
+    final ReverseTween<int> tween = ReverseTween<int>(IntTween(begin: 5, end: 9));
+    expect(tween.lerp(0.5), 7);
+    expect(tween.lerp(0.7), 6);
+  });
+
+  test('ColorTween', () {
+    final ColorTween tween = ColorTween(
+      begin: const Color(0xff000000),
+      end: const Color(0xffffffff)
+    );
+    expect(tween.lerp(0.0), const Color(0xff000000));
+    expect(tween.lerp(0.5), const Color(0xff7f7f7f));
+    expect(tween.lerp(0.7), const Color(0xffb2b2b2));
+    expect(tween.lerp(1.0), const Color(0xffffffff));
+  });
+
+  test('StepTween', () {
+    final StepTween tween = StepTween(begin: 5, end: 9);
+    expect(tween.lerp(0.5), 7);
+    expect(tween.lerp(0.7), 7);
+  });
+
+  test('CurveTween', () {
+    final CurveTween tween = CurveTween(curve: Curves.easeIn);
+    expect(tween.transform(0.0), 0.0);
+    expect(tween.transform(0.5), 0.31640625);
+    expect(tween.transform(1.0), 1.0);
+  });
 }