MockFileSystem.Directory.CreateDirectory throws IoException when directory exists and argument has trailing slash

[cmeeren]

MockFileSystem.Directory.CreateDirectory throws an IoException if the directory already exists and the argument to CreateDirectory() contains a trailing slash.

The following works correctly:

var fs = new MockFileSystem();
fs.AddDirectory(@"C:\test\"); // Trailing slash here doesn't matter
fs.Directory.CreateDirectory(@"C:\test"); // No trailing slash works correctly

The following throws an IOException:

var fs = new MockFileSystem();
fs.AddDirectory(@"C:\test\"); // Trailing slash here doesn't matter
fs.Directory.CreateDirectory(@"C:\test\"); // Trailing slash here causes error

System.IO.IOException : Cannot create "C:\test\" because a file or directory with the same name already exists.
   at System.IO.Abstractions.TestingHelpers.MockDirectory.CreateDirectory(String path, DirectorySecurity directorySecurity)
   at System.IO.Abstractions.TestingHelpers.MockDirectory.CreateDirectory(String path)

The correct behaviour is silently ignoring existing directories, like System.Io.Directory.CreateDirectory() does (documented behavior).

[tathamoddie]

Thanks for reporting! Can you share a pull request that fixes this?

[cmeeren]

Done. Added tests for the bug as well as for checking that return value is not null, as per MSDN documentation:

Return Value
Type: System.IO.DirectoryInfo

An object that represents the directory at the specified path. This object is returned regardless of whether a directory at the specified path already exists.