Merge pull request #156 from SublimeText/regex-assertion-output

Improved error text of regexp assertions.

Author: randy3k

tests/test_3141596.py

@@ -97,8 +97,10 @@ def real_wrapper(self):
 class UnitTestingTestCase(DeferrableTestCase):
 
     def assertRegexContains(self, txt, expr, msg=None):
-        m = re.search(expr, txt, re.MULTILINE)
-        self.assertIsNotNone(m, msg)
+        if re.search(expr, txt, re.MULTILINE) is None:
+            self.fail("String {!r} does not contain regexp {!r}.".format(
+                txt, expr
+            ))
 
     def assertOk(self, txt, msg=None):
         self.assertRegexContains(txt, r'^OK', msg)