WIP: Plugin fixtures

[DropD]

Add fixtures that plugins can use in their tests.

The FixtureManager class can set up a complete separate, temporary aiida environment for the duration of a test.

A simple use example is:

fixtures = FixtureManager()
fixtures.create_aiida_db()
fixtures.create_profile()
# now, the dbenv is loaded, all is ready
fixtures.destroy_all()
# now the db and all files are deleted

Alternatively the contextmanager may be used:

with plugin_fixture() as fixtures:
    fixtures.create_aiida_db()
    fixtures.create_profile()
    # ready for tests
# everything cleaned up

• An example of how to use it with unittest is included in aiida.utils.fixtures.PluginTestCase.
• An example for pytest is to be found in github.com/DropD/aiida-vasp in aiida_vasp.calcs.tests.test_base

[DropD]

Also of interest to @broeder-j and all other plugin developers

[ltalirz]

Very nice! Could you perhaps also add one example of how to use it? (or point me to where it is used)

[DropD]

updated the description with examples

[ltalirz]

@DropD Sorry if I am overlooking it - but where did you update the description?

[DropD]

The description of the PR

[DropD]

Examples are now also in the docstrings

[DropD]

Adding WIP status, because although destroy_all cleans u all the resources, it does not "unload" the dbenv. Thus, only one fixture manager can be used per test run, that means for all tests in an entire project. Therefore, there has to be at least a way to reset the database / repository to after migrations but before user / test interaction.

[ltalirz]

Thanks, indeed I overlooked that ;)
Sorry for keeping pressing on this, I'm sure for you it's trivial, but I still think it would be really helpful to have one simple, but complete unittest example in the aiida source code that makes use of the fixtures.

For example, should users simply inherit from aiida.utils.fixtures.PluginTestCase or should they re-implement what it does?
I think one actual 'demo' (can be in any other part of the code) would really make it easy to understand.

[ltalirz]

Let me know, when to go through it again!

[ltalirz]

simply prepend the test command by TEST_BACKEND='django' or TEST_BACKEND='sqlalchemy'

[ltalirz]

Very nice!
Now we need to add a test to the aiida plugin template!