Test cases from Cowlishaw, v2.57. All are pased cleanly.
diff --git a/Lib/test/decimaltestdata/decSingle.decTest b/Lib/test/decimaltestdata/decSingle.decTest
index c661fe4..aae9b37 100644
--- a/Lib/test/decimaltestdata/decSingle.decTest
+++ b/Lib/test/decimaltestdata/decSingle.decTest
@@ -17,7 +17,7 @@
 --   IBM UK, PO Box 31, Birmingham Road, Warwick CV34 5JL, UK         --
 --   mfc@uk.ibm.com                                                   --
 ------------------------------------------------------------------------
-version: 2.56
+version: 2.57
 
 -- decSingle tests
 dectest: dsBase