[WIP] TST: Clean up testing

[BenjaminBossan]

There is still some chaos in our test suite, despite recent efforts to refactor it. This PR tries to improve the situation a bit.

Some of the changes:

• for some PEFT methods, adjust some tolerances where necessary instead of skipping the whole test
• don't add return to pytest.skip, it's not necessary
• avoid self.skipTest, always use pytest.skip
• unused CONFIG_TESTING_KWARGS is removed
• factor out common skipping logic into dedicated functions
• many tests had code like: skip unless it's LoRA or IA³ or ... often, new PEFT methdos would actually work but were not added to this list, resulting in unnecessary skips
• make it so that LN Tuning is allowed to run with 0 active adapters (ping @DTennant)
• fix a bug in BOFT resulting in cayley_batch always returning float32 dtype (ping @zqiu24)
• transpose delta_weight for WaveFT merging if base layer is Conv1D (ping @Bilican)
• fix UnboundLocalError in C3A (ping @Phoveran)

For those that I pinged, this is just to let you know I made some fixes on PEFT methods that may concern you and ask you, if you have time, to double check them.

Errors not fixed in this PR (yet):

• failing DeLoRA tests will be fixed via FIX: DeLoRA adapter deletion issue #2853.
• failing OFT merge tests discussed here

[HuggingFaceDocBuilderDev]

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[BenjaminBossan]

@Phoveran I also noticed that we missed a TODO:

peft/src/peft/tuners/c3a/model.py

Line 33 in 2813b9c

The method is described in detail in [TODO].

[Phoveran]

Hi,

Thanks for the notice! I have added the paper link in my fork.
However, for the error, I tried to replicate it by python -m pytest tests/ -k c3a but failed. The test cases are all passed or skipped. Could you show me more details on it?

[BenjaminBossan]

I have added the paper link in my fork.

Nice, could you please create a PR?

However, for the error, I tried to replicate it by python -m pytest tests/ -k c3a but failed. The test cases are all passed or skipped. Could you show me more details on it?

You would have to use my branch from this PR. It removes a lot of skipping logic from the tests that I found unnecessary. But there is no need for you to get active, I already fixed the issue in C3A, my ping is just to let you know and for you to double check my change.

[Phoveran]

Got you. The PR is ready. Thanks!

[BenjaminBossan]

Note on some of the failing tests:

• OFT unmerging: see minor changes to OFT to make it faster #2805 (comment)
• DeLoRA adapter deletion and safe merge error message: FIX: DeLoRA adapter deletion issue #2853