Read unidata_version from unicodedata module.
Delete old NormalizationTest.txt if it doesn't match
unidata_version.
diff --git a/Lib/test/test_normalization.py b/Lib/test/test_normalization.py
index 99f8e4e..e9056cd 100644
--- a/Lib/test/test_normalization.py
+++ b/Lib/test/test_normalization.py
@@ -3,10 +3,17 @@
 
 import sys
 import os
-from unicodedata import normalize
+from unicodedata import normalize, unidata_version
 
 TESTDATAFILE = "NormalizationTest" + os.extsep + "txt"
-TESTDATAURL = "http://www.unicode.org/Public/5.1.0/ucd/" + TESTDATAFILE
+TESTDATAURL = "http://www.unicode.org/Public/" + unidata_version + "/ucd/" + TESTDATAFILE
+
+if os.path.exists(TESTDATAFILE):
+    f = open(TESTDATAFILE)
+    l = f.readline()
+    f.close()
+    if not unidata_version in l:
+        os.unlink(TESTDATAFILE)
 
 class RangeError(Exception):
     pass