Some clean ups for caching tests.

pkg/analysis_server/lib/src/index/lru_cache.dart

 // Copyright (c) 2014, 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 index.lru_cache;
 
 import 'dart:collection';
 
 
 /**
  * This handler is notified when an item is evicted from the cache.
  */
 typedef EvictionHandler<K, V>(K key, V value);
 
 /**
  * A hash-table based cache implementation.
  *
  * When it reaches the specified number of items, the item that has not been
- * accessed recently is evicted.
+ * accessed (both get and put) recently is evicted.
  */
 class LRUCache<K, V> {
   final LinkedHashSet<K> _lastKeys = new LinkedHashSet<K>();
   final HashMap<K, V> _map = new HashMap<K, V>();
   final int _maxSize;
   final EvictionHandler _handler;
 
   LRUCache(this._maxSize, [this._handler]);
 
   /**
@@ skipping 17 matching lines @@
     _map.remove(key);
   }
 
   /**
    * Associates the [key] with the given [value].
    *
    * If the cache is full, an item that has not been accessed recently is
    * evicted.
    */
   void put(K key, V value) {
+    _lastKeys.remove(key);
     _lastKeys.add(key);
     if (_lastKeys.length > _maxSize) {
       K evictedKey = _lastKeys.first;
       V evictedValue = _map.remove(evictedKey);
       _lastKeys.remove(evictedKey);
       if (_handler != null) {
         _handler(evictedKey, evictedValue);
       }
     }
     _map[key] = value;
   }
 }