Restore Unit Tests

[MelbourneDeveloper]

The commit d9b72a5 deleted a whole bunch of unit tests from the common library.

This is because it uses a lot of Mockito mocks without code generation and this doesn't work with type safety.

So, we need to generate the mocks and replace all the hand crafted mocks with the generated mocks. Also, you need to fix up compilation issues.

All the unit tests that don't compile have been tagged as skip-file and commented out. Try to uncommenting them to see the compilation errors.

It would be great if you could even fix up a few test files at a time.