diff --git a/Lib/unittest.py b/Lib/unittest.py
index f44769e..56c6da5 100644
--- a/Lib/unittest.py
+++ b/Lib/unittest.py
@@ -46,7 +46,7 @@
 
 __author__ = "Steve Purcell"
 __email__ = "stephen_purcell at yahoo dot com"
-__version__ = "#Revision: 1.56 $"[11:-2]
+__version__ = "#Revision: 1.57 $"[11:-2]
 
 import time
 import sys
@@ -540,7 +540,7 @@
         """Return a sorted sequence of method names found within testCaseClass
         """
         def isTestMethod(attrname, testCaseClass=testCaseClass, prefix=self.testMethodPrefix):
-            return attrname[:len(prefix)] == prefix and callable(getattr(testCaseClass, attrname))
+            return attrname.startswith(prefix) and callable(getattr(testCaseClass, attrname))
         testFnNames = filter(isTestMethod, dir(testCaseClass))
         for baseclass in testCaseClass.__bases__:
             for testFnName in self.getTestCaseNames(baseclass):