Added unit test to show the behavior difference of AlphaFS and System.IO

AlphaFS.UnitTest/AlphaFS.UnitTest.csproj

@@ -158,6 +158,7 @@
     <Compile Include="Directory Class\Directory.Delete\Directory.Delete_ExistingDirectory.cs" />
     <Compile Include="Directory Class\Directory.Delete\Directory.Delete_EmptyAsPath_ThrowsArgumentException.cs" />
     <Compile Include="Directory Class\Directory.Delete\Directory.Delete_NullAsPath_ThrowsArgumentNullException.cs" />
+    <Compile Include="Directory Class\Directory.Exists\Directory.Exists_AfterDeletion.cs" />
     <Compile Include="Directory Class\Directory_Timestamps\AlphaFS_Directory.CopyTimestamps.cs" />
     <Compile Include="Directory Class\Directory_Timestamps\AlphaFS_Directory.SetTimestamps_SymbolicLink.cs" />
     <Compile Include="File Class\AlphaFS_File_GetSize\AlphaFS_File.GetSize_AllStreams.cs" />

AlphaFS.UnitTest/Directory Class/Directory.Exists/Directory.Exists_AfterDeletion.cs

@@ -0,0 +1,241 @@
+/*  Copyright (C) 2008-2018 Peter Palotas, Jeffrey Jangli, Alexandr Normuradov
+ *  
+ *  Permission is hereby granted, free of charge, to any person obtaining a copy 
+ *  of this software and associated documentation files (the "Software"), to deal 
+ *  in the Software without restriction, including without limitation the rights 
+ *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 
+ *  copies of the Software, and to permit persons to whom the Software is 
+ *  furnished to do so, subject to the following conditions:
+ *  
+ *  The above copyright notice and this permission notice shall be included in 
+ *  all copies or substantial portions of the Software.
+ *  
+ *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
+ *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
+ *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
+ *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
+ *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
+ *  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 
+ *  THE SOFTWARE. 
+ */
+
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using System;
+using System.Runtime.InteropServices;
+using Microsoft.Win32.SafeHandles;
+
+namespace AlphaFS.UnitTest
+{
+   #region CreateFile Types
+   [Flags]
+   enum EFileAccess : uint
+   {
+      //
+      // Standart Section
+      //
+
+      AccessSystemSecurity = 0x1000000,   // AccessSystemAcl access type
+      MaximumAllowed = 0x2000000,     // MaximumAllowed access type
+
+      Delete = 0x10000,
+      ReadControl = 0x20000,
+      WriteDAC = 0x40000,
+      WriteOwner = 0x80000,
+      Synchronize = 0x100000,
+
+      StandardRightsRequired = 0xF0000,
+      StandardRightsRead = ReadControl,
+      StandardRightsWrite = ReadControl,
+      StandardRightsExecute = ReadControl,
+      StandardRightsAll = 0x1F0000,
+      SpecificRightsAll = 0xFFFF,
+
+      FILE_READ_DATA = 0x0001,        // file & pipe
+      FILE_LIST_DIRECTORY = 0x0001,       // directory
+      FILE_WRITE_DATA = 0x0002,       // file & pipe
+      FILE_ADD_FILE = 0x0002,         // directory
+      FILE_APPEND_DATA = 0x0004,      // file
+      FILE_ADD_SUBDIRECTORY = 0x0004,     // directory
+      FILE_CREATE_PIPE_INSTANCE = 0x0004, // named pipe
+      FILE_READ_EA = 0x0008,          // file & directory
+      FILE_WRITE_EA = 0x0010,         // file & directory
+      FILE_EXECUTE = 0x0020,          // file
+      FILE_TRAVERSE = 0x0020,         // directory
+      FILE_DELETE_CHILD = 0x0040,     // directory
+      FILE_READ_ATTRIBUTES = 0x0080,      // all
+      FILE_WRITE_ATTRIBUTES = 0x0100,     // all
+
+      //
+      // Generic Section
+      //
+
+      GenericRead = 0x80000000,
+      GenericWrite = 0x40000000,
+      GenericExecute = 0x20000000,
+      GenericAll = 0x10000000,
+
+      SPECIFIC_RIGHTS_ALL = 0x00FFFF,
+      FILE_ALL_ACCESS =
+      StandardRightsRequired |
+      Synchronize |
+      0x1FF,
+
+      FILE_GENERIC_READ =
+      StandardRightsRead |
+      FILE_READ_DATA |
+      FILE_READ_ATTRIBUTES |
+      FILE_READ_EA |
+      Synchronize,
+
+      FILE_GENERIC_WRITE =
+      StandardRightsWrite |
+      FILE_WRITE_DATA |
+      FILE_WRITE_ATTRIBUTES |
+      FILE_WRITE_EA |
+      FILE_APPEND_DATA |
+      Synchronize,
+
+      FILE_GENERIC_EXECUTE =
+      StandardRightsExecute |
+        FILE_READ_ATTRIBUTES |
+        FILE_EXECUTE |
+        Synchronize
+   }
+
+   [Flags]
+   public enum EFileShare : uint
+   {
+      /// <summary>
+      /// 
+      /// </summary>
+      None = 0x00000000,
+      /// <summary>
+      /// Enables subsequent open operations on an object to request read access. 
+      /// Otherwise, other processes cannot open the object if they request read access. 
+      /// If this flag is not specified, but the object has been opened for read access, the function fails.
+      /// </summary>
+      Read = 0x00000001,
+      /// <summary>
+      /// Enables subsequent open operations on an object to request write access. 
+      /// Otherwise, other processes cannot open the object if they request write access. 
+      /// If this flag is not specified, but the object has been opened for write access, the function fails.
+      /// </summary>
+      Write = 0x00000002,
+      /// <summary>
+      /// Enables subsequent open operations on an object to request delete access. 
+      /// Otherwise, other processes cannot open the object if they request delete access.
+      /// If this flag is not specified, but the object has been opened for delete access, the function fails.
+      /// </summary>
+      Delete = 0x00000004
+   }
+
+   public enum ECreationDisposition : uint
+   {
+      /// <summary>
+      /// Creates a new file. The function fails if a specified file exists.
+      /// </summary>
+      New = 1,
+      /// <summary>
+      /// Creates a new file, always. 
+      /// If a file exists, the function overwrites the file, clears the existing attributes, combines the specified file attributes, 
+      /// and flags with FILE_ATTRIBUTE_ARCHIVE, but does not set the security descriptor that the SECURITY_ATTRIBUTES structure specifies.
+      /// </summary>
+      CreateAlways = 2,
+      /// <summary>
+      /// Opens a file. The function fails if the file does not exist. 
+      /// </summary>
+      OpenExisting = 3,
+      /// <summary>
+      /// Opens a file, always. 
+      /// If a file does not exist, the function creates a file as if dwCreationDisposition is CREATE_NEW.
+      /// </summary>
+      OpenAlways = 4,
+      /// <summary>
+      /// Opens a file and truncates it so that its size is 0 (zero) bytes. The function fails if the file does not exist.
+      /// The calling process must open the file with the GENERIC_WRITE access right. 
+      /// </summary>
+      TruncateExisting = 5
+   }
+
+   [Flags]
+   public enum EFileAttributes : uint
+   {
+      Readonly = 0x00000001,
+      Hidden = 0x00000002,
+      System = 0x00000004,
+      Directory = 0x00000010,
+      Archive = 0x00000020,
+      Device = 0x00000040,
+      Normal = 0x00000080,
+      Temporary = 0x00000100,
+      SparseFile = 0x00000200,
+      ReparsePoint = 0x00000400,
+      Compressed = 0x00000800,
+      Offline = 0x00001000,
+      NotContentIndexed = 0x00002000,
+      Encrypted = 0x00004000,
+      Write_Through = 0x80000000,
+      Overlapped = 0x40000000,
+      NoBuffering = 0x20000000,
+      RandomAccess = 0x10000000,
+      SequentialScan = 0x08000000,
+      DeleteOnClose = 0x04000000,
+      BackupSemantics = 0x02000000,
+      PosixSemantics = 0x01000000,
+      OpenReparsePoint = 0x00200000,
+      OpenNoRecall = 0x00100000,
+      FirstPipeInstance = 0x00080000
+   }
+#endregion
+
+   public partial class ExistsTest
+   {
+      #region CreateFile
+      [DllImport("kernel32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall, SetLastError = true)]
+      public static extern SafeFileHandle CreateFile(
+         string lpFileName,
+         uint dwDesiredAccess,
+         uint dwShareMode,
+         IntPtr SecurityAttributes,
+         uint dwCreationDisposition,
+         uint dwFlagsAndAttributes,
+         IntPtr hTemplateFile
+      );
+      #endregion
+
+      // Pattern: <class>_<function>_<scenario>_<expected result>
+
+      [TestMethod]
+      public void Directory_Exists_AfterDeletion_LocalAndNetwork_Success()
+      {
+         Directory_Exists_AfterDeletion(false);
+         Directory_Exists_AfterDeletion(true);
+      }
+
+
+      private void Directory_Exists_AfterDeletion(bool isNetwork)
+      {
+         using (var tempRoot = new TemporaryDirectory(isNetwork))
+         {
+            var folder = tempRoot.CreateDirectory();
+
+            Console.WriteLine("Input Directory Path: [{0}]", folder.FullName);
+
+            //This simulates the behaviour of having a directory open in Windows Explorer and the deleting the directory
+            //To obtain a handle to an existing directory, call the CreateFile function with the FILE_FLAG_BACKUP_SEMANTICS flag. https://docs.microsoft.com/en-us/windows/desktop/fileio/obtaining-a-handle-to-a-directory
+            var ptr = CreateFile(folder.FullName, (uint)EFileAccess.GenericRead, (uint)EFileShare.Delete, IntPtr.Zero, (uint)ECreationDisposition.OpenAlways, (uint)EFileAttributes.BackupSemantics, IntPtr.Zero);
+
+            folder.Delete();
+
+            var existsSysIO = System.IO.Directory.Exists(folder.FullName);
+            var existsAlpha = Alphaleonis.Win32.Filesystem.Directory.Exists(folder.FullName);
+
+            ptr.Close();
+
+            Assert.AreEqual(existsSysIO, existsAlpha);
+         }
+
+         Console.WriteLine();
+      }
+   }
+}