add test for passing weights to ensemble posterior

[janfb]

There was a bug in the type checking for the weights passed to the ensemble posterior, see #1299

This was not detected before because we are missing a test case for this.

To fix this issues, add a minimal test similar to here:

sbi/tests/ensemble_test.py

Line 57 in 18b1141

def test_c2st_posterior_ensemble_on_linearGaussian(

e.g., by passing uniform weights as list or as tensors (both cases should be covered. Ideally, we do not run the entire again, but just a minimal version that tests the API: minimal training, only two posteriors etc.

[samadpls]

Hi @janfb, can I work on this issue?

[janfb]

Hi @samadpls , yes please do. do you have a plan how to tackle this, or do you need more input?

[samadpls]

I'll follow the steps you mentioned above to add a targeted test for weights in EnsemblePosterior, verifying compatibility for both lists and tensors. I'd appreciate any input you might have on additional cases to include

[janfb]

Sure. the current test tests for the accuracy of the posteriors as well, and is therefore marked as slow.

Thinking about it, it would make sense to leave this one as it is, and to create a new test that includes the cases with different types of weights, but that does not check for posterior accuracy. It should only test the API and be rather fast (please test this), and therefore would not need the @slow mark.

Thanks!