Add package creation to tests

[nyggus]

[patrickboateng]

So I guess the package creation will be done in a separate test right? And I am guessing the whole design will be:

1. Create the virtual environment.
2. Install the package in the virtual environment.

[nyggus]

Yes. But I am not sure these should be separate tests, as in order to run such a test, you need to create the package. So, this should be tested in one run, so in the current test functions.

These will become impressive integration tests, but as I wrote elsewhere, we will also implement unit tests.