Add test folder to package source distribution

[j-emberton]

Is your feature request related to a problem? Please describe.

Pyrealm is distributed from PyPI without the tests included. This means that anyone who wants to build Pyrealm themselves doesn't have direct access to the tests to verify their build.

This is relevant to people and orgs (e.g. anaconda etc) who like to build their own packages.

Describe the solution you'd like

Add the tests to the source distribution

[davidorme]

That seems sensible - I hadn't really looked at what is included in the source distribution. I explicitly included the pyrealm_build_data package in source, which is excluded from the binary distributions, but it doesn't include anything else needed to build and test the package, so the source distribution doesn't really stand alone.

It's not just tests, really - the docs should probably go in too?

[j-emberton]

Yes I'd agree documentation would be a useful addition.