Add more tests

[damienmg]

This is a meta bug for the list of tests to add. Ping here if you are interested in contributing in unit testing.

[etotientz]

I am interested.Please share the detail.

[damienmg]

There are not much details, the current tests only test the Command utility and there is way more class than can be tested (e.g. BazelCommand by using a stub for Bazel).