Add more tests to increase code coverage

[kirtangajjar]

Currently the code in /features contains very basic tests. Only the "happy" paths. We should add extensive tests which strives to execute each and every execution path.

Also as discussed previously, we need to be more strict about "No new features without tests" policy.

This might reduce our speed initially but will definitely help us in long run. Also we should look into code coverage tools to gauge how many execution paths are being tested.

[mrrobot47]

Also, the tests are currently present only in the site-types and EasyEngine core. Need to add tests to all the other command repos.