Test cases from Cowlishaw, v2.57. All are pased cleanly.
diff --git a/Lib/test/decimaltestdata/ddRemainder.decTest b/Lib/test/decimaltestdata/ddRemainder.decTest
index c7ea762..d805a48 100644
--- a/Lib/test/decimaltestdata/ddRemainder.decTest
+++ b/Lib/test/decimaltestdata/ddRemainder.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
precision: 16
maxExponent: 384
@@ -581,6 +581,19 @@
ddrem1057 remainder -1e-277 1e+311 -> -1E-277
ddrem1058 remainder -1e-277 -1e+311 -> -1E-277
+-- destructive subtract
+ddrem1101 remainder 1234567890123456 1.000000000000001 -> 0.765432109876546
+ddrem1102 remainder 1234567890123456 1.00000000000001 -> 0.65432109876557
+ddrem1103 remainder 1234567890123456 1.0000000000001 -> 0.5432109876668
+ddrem1104 remainder 1234567890123455 4.000000000000001 -> 2.691358027469137
+ddrem1105 remainder 1234567890123456 4.000000000000001 -> 3.691358027469137
+ddrem1106 remainder 1234567890123456 4.9999999999999 -> 0.6913578024696
+ddrem1107 remainder 1234567890123456 4.99999999999999 -> 3.46913578024691
+ddrem1108 remainder 1234567890123456 4.999999999999999 -> 1.246913578024691
+ddrem1109 remainder 1234567890123456 5.000000000000001 -> 0.753086421975309
+ddrem1110 remainder 1234567890123456 5.00000000000001 -> 3.53086421975310
+ddrem1111 remainder 1234567890123456 5.0000000000001 -> 1.3086421975314
+
-- Null tests
ddrem1000 remainder 10 # -> NaN Invalid_operation
ddrem1001 remainder # 10 -> NaN Invalid_operation