sftp-mkdir.diff

diff --git a/tests/test_sftp.py b/tests/test_sftp.py
index 6a514ac..ddb87cf 100644
--- a/tests/test_sftp.py
+++ b/tests/test_sftp.py
@@ -1,7 +1,6 @@
 from copy import deepcopy
 from paramiko import Transport
 from paramiko.channel import Channel
-from paramiko.sftp_attr import SFTPAttributes
 from paramiko.sftp_client import SFTPClient
 import pytest
 import sys
@@ -127,6 +126,17 @@ def test_sftpserver_mkdir(content, sftpclient):
     assert set(sftpclient.listdir("/a")) == set(["b", "c", "f", "x"])


+def test_sftpserver_mkdir_existing(content, sftpclient):
+    """
+    Executing mkdir on an existing directory path should raise an IOError
+    indicating that the directory already exists without affecting the
+    content of the existing directory.
+    """
+    with pytest.raises(IOError):
+        sftpclient.mkdir('/a')
+    assert set(sftpclient.listdir("/a")) == set(["b", "c", "f"])
+
+
 def test_sftpserver_chmod(content, sftpclient):
     # coverage
     sftpclient.chmod("/a/b", 1)