Index: Lib/pickletools.py
===================================================================
--- Lib/pickletools.py	(revision 82259)
+++ Lib/pickletools.py	(working copy)
@@ -2326,8 +2326,13 @@
            }
 
 def _test():
-    import doctest
-    return doctest.testmod()
+    import sys
+    if len(sys.argv) == 2:
+        with open(sys.argv[1], 'br') as picklefile:
+            dis(picklefile)
+    else:
+        import doctest
+        return doctest.testmod()
 
 if __name__ == "__main__":
     _test()