Improve unit tests

[dinkopehar]

mockData currently has unit tests, but they are not complete. Complete tests by adding missing tests for some sections, test for throws and generally rethink about improving testing step.

[dinkopehar]

Update:

I'll leave this for someone who is newcomer to GitHub to contribute. So anyone who is willing to contribute can write unit tests and I'll place him in contributors list.

Branch is called ops-improve_unit_tests.