Modifies test_get_long_path_name_winr32() to fix #4629 on ipython/ipython.

IPython/utils/tests/test_path.py

@@ -453,8 +453,9 b' def test_get_ipython_module_path():'
 def test_get_long_path_name_win32():
     with TemporaryDirectory() as tmpdir:
 
-        # Make a long path.
-        long_path = os.path.join(tmpdir, u'this is my long path name')
+        # Make a long path. Expands the path of tmpdir prematurely to make sure only the 
+        # last part is different later on.
+        long_path = os.path.join(path.get_long_path_name(tmpdir), u'this is my long path name')
         os.makedirs(long_path)
 
         # Test to see if the short path evaluates correctly.