mcs/class/System.ComponentModel.Composition/Tests/ComponentModelUnitTest/Microsoft/Internal/Collections/WeakReferenceCollectionTests.cs

   1 // -----------------------------------------------------------------------\r
   2 // Copyright (c) Microsoft Corporation.  All rights reserved.\r
   3 // -----------------------------------------------------------------------\r
   4 using System;\r
   5 using System.Collections;\r
   6 using System.Collections.Generic;\r
   7 using System.UnitTesting;\r
   8 using Microsoft.VisualStudio.TestTools.UnitTesting;\r
   9 \r
  10 namespace Microsoft.Internal.Collections\r
  11 {\r
  12     [TestClass]\r
  13     public class WeakReferenceCollectionTests\r
  14     {\r
  15         [TestMethod]\r
  16         public void Add_ObjectShouldGetCollected()\r
  17         {\r
  18             var obj = new object();\r
  19             var wrc = new WeakReferenceCollection<object>();\r
  20 \r
  21             wrc.Add(obj);\r
  22 \r
  23             var wr = new WeakReference(obj);\r
  24             obj = null;\r
  25 \r
  26             Assert.IsNotNull(wr.Target, "Object should NOT have been collected yet!");\r
  27 \r
  28             GC.Collect();\r
  29             GC.WaitForPendingFinalizers();\r
  30 \r
  31             Assert.IsNull(wr.Target, "Object should have been collected!");\r
  32 \r
  33             GC.KeepAlive(wrc);\r
  34         }\r
  35 \r
  36         [TestMethod]\r
  37         public void Remove_ObjectShouldGetRemoved()\r
  38         {\r
  39             var obj = new object();\r
  40             var wrc = new WeakReferenceCollection<object>();\r
  41 \r
  42             wrc.Add(obj);\r
  43 \r
  44             Assert.AreEqual(1, wrc.AliveItemsToList().Count, "Should have 1 item!");\r
  45             \r
  46             wrc.Remove(obj);\r
  47 \r
  48             Assert.AreEqual(0, wrc.AliveItemsToList().Count, "Should have 0 item!");\r
  49         }\r
  50 \r
  51         [TestMethod]\r
  52         public void AliveItemsToList_ShouldReturnAllItems()\r
  53         {\r
  54             var list = new object[] {new object(), new object(), new object()};\r
  55             var wrc = new WeakReferenceCollection<object>();\r
  56 \r
  57             foreach (object obj in list)\r
  58             {\r
  59                 wrc.Add(obj);\r
  60             }\r
  61 \r
  62             Assert.AreEqual(list.Length, wrc.AliveItemsToList().Count, "Should have same number of items!");\r
  63         }\r
  64 \r
  65         [TestMethod]\r
  66         public void AliveItemsToList_ShouldReturnAllAliveItems()\r
  67         {\r
  68             var list = new object[] { new object(), new object(), new object() };\r
  69             var wrc = new WeakReferenceCollection<object>();\r
  70 \r
  71             var obj1 = new object();\r
  72             wrc.Add(obj1);\r
  73 \r
  74             foreach (object obj in list)\r
  75             {\r
  76                 wrc.Add(obj);\r
  77             }\r
  78 \r
  79             var obj2 = new object();\r
  80             wrc.Add(obj2);\r
  81 \r
  82             Assert.AreEqual(list.Length + 2, wrc.AliveItemsToList().Count, "Should have same number of items!");\r
  83 \r
  84             obj1 = obj2 = null;\r
  85 \r
  86             GC.Collect();\r
  87             GC.WaitForPendingFinalizers();\r
  88 \r
  89             var aliveItems = wrc.AliveItemsToList();\r
  90             Assert.AreEqual(list.Length, aliveItems.Count, "Should have 2 less items!");\r
  91 \r
  92             Assert.AreEqual(list[0], aliveItems[0]);\r
  93             Assert.AreEqual(list[1], aliveItems[1]);\r
  94             Assert.AreEqual(list[2], aliveItems[2]);\r
  95         }\r
  96 \r
  97         [TestMethod]\r
  98         public void AliveItemsToList_ShouldReturnEmpty()\r
  99         {\r
 100             var wrc = new WeakReferenceCollection<object>();\r
 101             Assert.AreEqual(0, wrc.AliveItemsToList().Count, "Should have 0 items!");\r
 102         }\r
 103     }\r
 104 }