expose select test fixtures in the api

[atravitz]

@ianmkenney suggested exposing some of gufe's test data fixtures for use in downstream packages' testing or examples. We can play around with this idea and see if we like it.

[IAlibay]

If it's to be used for examples, it might be hard to reuse pytest fixtures. How about just exposing the data in a way that we can easily access in a data specific package? For example you could see the way we store trajectory files for MDAnalysisTests.

[ianmkenney]

If it's to be used for examples, it might be hard to reuse pytest fixtures. How about just exposing the data in a way that we can easily access in a data specific package? For example you could see the way we store trajectory files for MDAnalysisTests.

This was the idea since using gufe fixtures in stratocaster wasn't going very well. Once there is a data module that contains an object generator, such as gufe.data.network.benzene_variants_star_map, we could reuse them in our own fixtures as before.

@pytest.fixture
def benzene_variants_star_map():
    return gufe.data.network.benzene_variants_star_map()