Tweaks for review comments.

pkg/analysis_server/test/index/file_page_manager_test.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 test.index.file_page_manager;
 
+import 'dart:collection';
 import 'dart:io';
 import 'dart:math';
 import 'dart:typed_data';
 
 import 'package:analysis_server/src/index/b_plus_tree.dart';
 import 'package:analysis_server/src/index/file_page_manager.dart';
 import 'package:analysis_server/src/index/page_node_manager.dart';
 import 'package:path/path.dart' as pathos;
 import 'package:unittest/unittest.dart';
 
@@ skipping 46 matching lines @@
     NodeManager<int, String, int> nodeManager = new PageNodeManager<int,
         String>(manager, Uint32Codec.INSTANCE, new FixedStringCodec(7));
     nodeManager = new CachingNodeManager(nodeManager, 32, 32);
     BPlusTree<int, String, int> tree = new BPlusTree(_intComparator,
         nodeManager);
     // insert
     int maxKey = 1000000;
     int tryCount = 1000;
     Set<int> keys = new Set<int>();
     {
-      Random random = new Random();
+      Random random = new Random(37);
       for (int i = 0; i < tryCount; i++) {
         int key = random.nextInt(maxKey);
         keys.add(key);
         tree.insert(key, 'V$key');
       }
     }
     // find every
     for (int key in keys) {
       expect(tree.find(key), 'V$key');
     }
     // remove random keys
     {
-      Random random = new Random();
+      Random random = new Random(37);
+      Set<int> removedKeys = new HashSet<int>();
       for (int key in new Set<int>.from(keys)) {
         if (random.nextBool()) {
+          removedKeys.add(key);
           keys.remove(key);
           expect(tree.remove(key), 'V$key');
         }
       }
+      // check the removed keys are actually gone
+      for (int key in removedKeys) {
+        expect(tree.find(key), isNull);
+      }
     }
     // find every remaining key
     for (int key in keys) {
       expect(tree.find(key), 'V$key');
     }
   }
 
   void test_free_double() {
     int id = manager.alloc();
     manager.free(id);
     expect(() {
       manager.free(id);
     }, throws);
   }
 
   void test_writeRead() {
     // write
     int id1 = manager.alloc();
     int id2 = manager.alloc();
     manager.write(id1, new Uint8List.fromList(new List.filled(pageSize, 1)));
     manager.write(id2, new Uint8List.fromList(new List.filled(pageSize, 2)));
     // read
     expect(manager.read(id1), everyElement(1));
     expect(manager.read(id2), everyElement(2));
   }
 }