Improve the intergrity checking for "gradle wrapper". (#26069)

packages/flutter_tools/test/cache_test.dart

diff --git a/packages/flutter_tools/test/cache_test.dart b/packages/flutter_tools/test/cache_test.dart
index 36bf2ce..03912cb 100644
--- a/packages/flutter_tools/test/cache_test.dart
+++ b/packages/flutter_tools/test/cache_test.dart
@@ -51,6 +51,36 @@
   });
 
   group('Cache', () {
+    final MockCache mockCache = MockCache();
+    final MemoryFileSystem fs = MemoryFileSystem();
+
+    testUsingContext('Gradle wrapper should not be up to date, if some cached artifact is not available', () {
+      final GradleWrapper gradleWrapper = GradleWrapper(mockCache);
+      final Directory directory = fs.directory('/Applications/flutter/bin/cache');
+      directory.createSync(recursive: true);
+      fs.file(fs.path.join(directory.path, 'artifacts', 'gradle_wrapper', 'gradle', 'wrapper', 'gradle-wrapper.jar')).createSync(recursive: true);
+      when(mockCache.getCacheDir(fs.path.join('artifacts', 'gradle_wrapper'))).thenReturn(fs.directory(fs.path.join(directory.path, 'artifacts', 'gradle_wrapper')));
+      expect(gradleWrapper.isUpToDateInner(), false);
+    }, overrides: <Type, Generator>{
+      Cache: ()=> mockCache,
+      FileSystem: () => fs
+    });
+
+    testUsingContext('Gradle wrapper should be up to date, only if all cached artifact are available', () {
+      final GradleWrapper gradleWrapper = GradleWrapper(mockCache);
+      final Directory directory = fs.directory('/Applications/flutter/bin/cache');
+      directory.createSync(recursive: true);
+      fs.file(fs.path.join(directory.path, 'artifacts', 'gradle_wrapper', 'gradle', 'wrapper', 'gradle-wrapper.jar')).createSync(recursive: true);
+      fs.file(fs.path.join(directory.path, 'artifacts', 'gradle_wrapper', 'gradlew')).createSync(recursive: true);
+      fs.file(fs.path.join(directory.path, 'artifacts', 'gradle_wrapper', 'gradlew.bat')).createSync(recursive: true);
+
+      when(mockCache.getCacheDir(fs.path.join('artifacts', 'gradle_wrapper'))).thenReturn(fs.directory(fs.path.join(directory.path, 'artifacts', 'gradle_wrapper')));
+      expect(gradleWrapper.isUpToDateInner(), true);
+    }, overrides: <Type, Generator>{
+      Cache: ()=> mockCache,
+      FileSystem: () => fs
+    });
+
     test('should not be up to date, if some cached artifact is not', () {
       final CachedArtifact artifact1 = MockCachedArtifact();
       final CachedArtifact artifact2 = MockCachedArtifact();
@@ -132,3 +162,4 @@
 class MockRandomAccessFile extends Mock implements RandomAccessFile {}
 class MockCachedArtifact extends Mock implements CachedArtifact {}
 class MockInternetAddress extends Mock implements InternetAddress {}
+class MockCache extends Mock implements Cache {}
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