Update testing.rst

Author: akshaydayma

docs/source/contributing/testing.rst

@@ -1,8 +1,22 @@
-=======
-Testing
-=======
 
-.. admonition:: ToDo
-   :class: custom-admonition-todo
+  ###############
+   TESTING
+ ###############
 
-   We need to create this content.
+*   You've written and tested your code, but before sending code out for review, run all the tests for the whole tree to make sure the changes don't break other           
+    packages or programs.
+
+*    After running for a while and printing a lot of testing output, the command should finish by printing,
+
+     ALL TESTS PASSED
+
+
+*    In the  (https://github.com/nexB/, For Example) repositories
+     Run the tests for the entire repository.
+
+*    If you're concerned about the build status, you can check the Build Dashboard. Test failures may also be caught  in code review.
+
+*    Some repositories will have different testing infrastructures, so always check the documentation for the repository in which you are working The README file in the
+     root of the repository will usually have this information.
+
+