added commonprefix test cases
diff --git a/Lib/test/test_ntpath.py b/Lib/test/test_ntpath.py
index ae9054b..11f2f44 100644
--- a/Lib/test/test_ntpath.py
+++ b/Lib/test/test_ntpath.py
@@ -37,6 +37,12 @@
tester('ntpath.abspath("C:\\")', "C:\\")
+tester('ntpath.commonprefix(["/home/swenson/spam", "/home/swen/spam"])',
+ "/home/swen")
+tester('ntpath.commonprefix(["\\home\\swen\\spam", "\\home\\swen\\eggs"])',
+ "\\home\\swen\\")
+tester('ntpath.commonprefix(["/home/swen/spam", "/home/swen/spam"])',
+ "/home/swen/spam")
if errors:
print str(errors) + " errors."