fix checkLockAcquired: support re-entrant locking (#9272)
* fix checkLockAcquired: support re-entrant locking
* add test; address comments
* add comment
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 {}
