[Tests] Optimise the tests

[swapnilgm]

Feature (What you would like to be added): Create scalable and reusable test framework for testing. Optimise the time consumed for running all the tests.

Motivation (Why is this needed?): Currently, we have duplicate code used for setting up environment like bootstrapping etcd or pushing test specific data to etcd. Now its causing extra time consumption while running tests. We are not able to run many tests in parallel. Thorough the experience we now have enough idea to make generic and reusable code.

[abdasgupta]

Test coverages are increased and lots of unit test cases added using mock tests. But we need to explore if we can further optimize some test cases to run in parallel