Fix for the change/save/undo race condition.

pkg/analyzer/test/src/util/lru_map_test.dart

+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library test.src.util.lru_map;
+
+import 'package:analyzer/src/util/lru_map.dart';
+import 'package:unittest/unittest.dart';
+
+import '../../reflective_tests.dart';
+
+
+main() {
+  groupSep = ' | ';
+  runReflectiveTests(_LRUCacheTest);
+}
+
+
+@reflectiveTest
+class _LRUCacheTest {
+  LRUMap<int, String> cache = new LRUMap<int, String>(3);
+
+  void test_evict_notGet() {
+    List<int> evictedKeys = new List<int>();
+    List<String> evictedValues = new List<String>();
+    cache = new LRUMap<int, String>(3, (int key, String value) {
+      evictedKeys.add(key);
+      evictedValues.add(value);
+    });
+    // fill
+    cache.put(1, 'A');
+    cache.put(2, 'B');
+    cache.put(3, 'C');
+    // access '1' and '3'
+    cache.get(1);
+    cache.get(3);
+    // put '4', evict '2'
+    cache.put(4, 'D');
+    expect(cache.get(1), 'A');
+    expect(cache.get(2), isNull);
+    expect(cache.get(3), 'C');
+    expect(cache.get(4), 'D');
+    // check eviction listener
+    expect(evictedKeys, contains(2));
+    expect(evictedValues, contains('B'));
+  }
+
+  void test_evict_notPut() {
+    List<int> evictedKeys = new List<int>();
+    List<String> evictedValues = new List<String>();
+    cache = new LRUMap<int, String>(3, (int key, String value) {
+      evictedKeys.add(key);
+      evictedValues.add(value);
+    });
+    // fill
+    cache.put(1, 'A');
+    cache.put(2, 'B');
+    cache.put(3, 'C');
+    // put '1' and '3'
+    cache.put(1, 'AA');
+    cache.put(3, 'CC');
+    // put '4', evict '2'
+    cache.put(4, 'D');
+    expect(cache.get(1), 'AA');
+    expect(cache.get(2), isNull);
+    expect(cache.get(3), 'CC');
+    expect(cache.get(4), 'D');
+    // check eviction listener
+    expect(evictedKeys, contains(2));
+    expect(evictedValues, contains('B'));
+  }
+
+  void test_putGet() {
+    // fill
+    cache.put(1, 'A');
+    cache.put(2, 'B');
+    cache.put(3, 'C');
+    // check
+    expect(cache.get(1), 'A');
+    expect(cache.get(2), 'B');
+    expect(cache.get(3), 'C');
+    expect(cache.get(4), isNull);
+  }
+
+  void test_remove() {
+    cache.put(1, 'A');
+    cache.put(2, 'B');
+    cache.put(3, 'C');
+    // remove
+    cache.remove(1);
+    cache.remove(3);
+    // check
+    expect(cache.get(1), isNull);
+    expect(cache.get(2), 'B');
+    expect(cache.get(3), isNull);
+  }
+}