diff --git a/packages/flutter_tools/test/src/cache_test.dart b/packages/flutter_tools/test/src/cache_test.dart
new file mode 100644
index 0000000..5c7a401
--- /dev/null
+++ b/packages/flutter_tools/test/src/cache_test.dart
@@ -0,0 +1,67 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:async';
+
+import 'package:file/file.dart';
+import 'package:file/memory.dart';
+import 'package:mockito/mockito.dart';
+import 'package:test/test.dart';
+import 'package:platform/platform.dart';
+
+import 'package:flutter_tools/src/cache.dart';
+
+import 'context.dart';
+
+void main() {
+  group('$Cache.checkLockAcquired', () {
+    setUp(() {
+      Cache.enableLocking();
+    });
+
+    tearDown(() {
+      // Restore locking to prevent potential side-effects in
+      // tests outside this group (this option is globally shared).
+      Cache.enableLocking();
+    });
+
+    test('should throw when locking is not acquired', () {
+      expect(() => Cache.checkLockAcquired(), throwsStateError);
+    });
+
+    test('should not throw when locking is disabled', () {
+      Cache.disableLocking();
+      Cache.checkLockAcquired();
+    });
+
+    testUsingContext('should not throw when lock is acquired', () async {
+      await Cache.lock();
+      Cache.checkLockAcquired();
+    }, overrides: <Type, Generator>{
+      FileSystem: () => new MockFileSystem(),
+    });
+
+    testUsingContext('should not throw when FLUTTER_ALREADY_LOCKED is set', () async {
+      Cache.checkLockAcquired();
+    }, overrides: <Type, Generator>{
+      Platform: () => new FakePlatform()..environment = <String, String>{'FLUTTER_ALREADY_LOCKED': 'true'},
+    });
+  });
+}
+
+class MockFileSystem extends MemoryFileSystem {
+  @override
+  File file(dynamic path) {
+    return new MockFile();
+  }
+}
+
+class MockFile extends Mock implements File {
+  @override
+  Future<RandomAccessFile> open({FileMode mode: FileMode.READ}) async {
+    return new MockRandomAccessFile();
+  }
+}
+
+class MockRandomAccessFile extends Mock implements RandomAccessFile {}