Update README.md

Author: Joseph Luce

testing/README.md

@@ -1,4 +1,8 @@
+# Unit Testing in Python
 - https://nedbatchelder.com/ 
 - http://www.diveintopython.net/unit_testing/index.html
 - https://www.youtube.com/watch?v=1Lfv5tUGsn8&index=30&list=PLi01XoE8jYohWFPpC17Z-wWhPOSuh8Er-
 - https://jeffknupp.com/blog/2013/12/09/improve-your-python-understanding-unit-testing/
+
+# Mocking in Python
+- https://www.youtube.com/watch?v=zW0f4ZRYF5M