Merge pull request diffblue#299 from diffblue/owen-jones-diffblue/small-fix-to-end-to-end-driver

Only print message if test failed

Author: owen-jones-diffblue

regression/end_to_end/driver.py

@@ -52,7 +52,8 @@ def __enter__(self):
         return self
 
     def __exit__(self, exc_type, exc_value, traceback):
-        print("Failure may relate to command: ", self.cmdline, file=sys.stderr)
+        if exc_value is not None:
+            print("Failure may relate to command: ", self.cmdline, file=sys.stderr)
 
 def quote_pathnames_in_command_line(cmdline):
     assert isinstance(cmdline, list) and len(cmdline) > 0