Check for trailing backslash. Fixes #593656.
diff --git a/Lib/test/pickletester.py b/Lib/test/pickletester.py
index 3dc7901..2294c3d 100644
--- a/Lib/test/pickletester.py
+++ b/Lib/test/pickletester.py
@@ -199,6 +199,7 @@
                     "'abc", # quote is not closed
                     "'abc\"", # open quote and close quote don't match
                     "'abc'   ?", # junk after close quote
+                    "'\\'", # trailing backslash
                     # some tests of the quoting rules
                     #"'abc\"\''",
                     #"'\\\\a\'\'\'\\\'\\\\\''",