bug 411099: chdir() isn't saving the cwd in a normalized way. added test.

paramiko/sftp_client.py

@@ -503,7 +503,8 @@ class SFTPClient (BaseSFTP):
         doesn't really have the concept of a current working directory, this
         is emulated by paramiko.  Once you use this method to set a working
         directory, all operations on this SFTPClient object will be relative
-        to that path.
+        to that path. You can pass in C{None} to stop using a current working
+        directory.
 
         @param path: new current working directory
         @type path: str
@@ -512,9 +513,12 @@ class SFTPClient (BaseSFTP):
 
         @since: 1.4
         """
+        if path is None:
+            self._cwd = None
+            return
         if not stat.S_ISDIR(self.stat(path).st_mode):
             raise SFTPError(errno.ENOTDIR, "%s: %s" % (os.strerror(errno.ENOTDIR), path))
-        self._cwd = self.normalize(path)
+        self._cwd = self.normalize(path).encode('utf-8')
 
     def getcwd(self):
         """

tests/test_sftp.py

@@ -637,7 +637,19 @@ class SFTPTest (unittest.TestCase):
             self.fail('exception ' + e)
         sftp.unlink(FOLDER + '/\xc3\xbcnic\xc3\xb8\x64\x65')
 
-    def test_L_bad_readv(self):
+    def test_L_utf8_chdir(self):
+        sftp.mkdir(FOLDER + u'\u00fcnic\u00f8de')
+        try:
+            sftp.chdir(FOLDER + u'\u00fcnic\u00f8de')
+            f = sftp.open('something', 'w')
+            f.write('okay')
+            f.close()
+            sftp.unlink('something')
+        finally:
+            sftp.chdir(None)
+            sftp.rmdir(FOLDER + u'\u00fcnic\u00f8de')
+
+    def test_M_bad_readv(self):
         """
         verify that readv at the end of the file doesn't essplode.
         """