Fix error when resetting configurations in tear down phase (#114468)

* move _verifyInvariants

* fix

* fix (mimic import test_api.dart)

* fix

* Update binding.dart

* add tests

* try to move

* Revert "try to move"

This reverts commit d3c466d226cc1abe195af83a2630c70f08e25d7d.

* Update binding.dart

packages/flutter_test/lib/src/binding.dart

@@ -15,6 +15,7 @@ import 'package:flutter/services.dart';
 import 'package:flutter/widgets.dart';
 import 'package:stack_trace/stack_trace.dart' as stack_trace;
 import 'package:test_api/expect.dart' show fail;
+import 'package:test_api/scaffolding.dart'; // ignore: deprecated_member_use
 import 'package:test_api/test_api.dart' as test_package show Timeout; // ignore: deprecated_member_use
 import 'package:vector_math/vector_math_64.dart';
 
@@ -919,6 +920,13 @@ abstract class TestWidgetsFlutterBinding extends BindingBase
     // So that we can assert that it remains the same after the test finishes.
     _beforeTestCheckIntrinsicSizes = debugCheckIntrinsicSizes;
 
+    bool shouldTearDownVerifyInvariants = false;
+    addTearDown(() {
+      if (shouldTearDownVerifyInvariants) {
+        _verifyTearDownInvariants();
+      }
+    });
+
     runApp(Container(key: UniqueKey(), child: _preTestMessage)); // Reset the tree to a known state.
     await pump();
     // Pretend that the first frame produced in the test body is the first frame
@@ -949,6 +957,7 @@ abstract class TestWidgetsFlutterBinding extends BindingBase
       _verifyErrorWidgetBuilderUnset(errorWidgetBuilderBeforeTest);
       _verifyShouldPropagateDevicePointerEventsUnset(shouldPropagateDevicePointerEventsBeforeTest);
       _verifyInvariants();
+      shouldTearDownVerifyInvariants = true;
     }
 
     assert(inTest);
@@ -958,6 +967,11 @@ abstract class TestWidgetsFlutterBinding extends BindingBase
   late bool _beforeTestCheckIntrinsicSizes;
 
   void _verifyInvariants() {
+    // subclasses such as AutomatedTestWidgetsFlutterBinding overrides this
+    // to perform more verifications.
+  }
+
+  void _verifyTearDownInvariants() {
     assert(debugAssertNoTransientCallbacks(
       'An animation is still running even after the widget tree was disposed.'
     ));

packages/flutter_test/test/bindings_test.dart

@@ -12,6 +12,7 @@ library;
 import 'dart:async';
 import 'dart:io';
 
+import 'package:flutter/scheduler.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
@@ -102,4 +103,16 @@ void main() {
     });
     expect(responded, true);
   });
+
+  group('should be able to reset values in either tearDown or end of function', () {
+    testWidgets('addTearDown should work', (WidgetTester tester) async {
+      timeDilation = 2;
+      addTearDown(() => timeDilation = 1);
+    });
+
+    testWidgets('directly reset should work', (WidgetTester tester) async {
+      timeDilation = 2;
+      timeDilation = 1;
+    });
+  });
 }