solve Illegal seek in wandb teardown (test suite)
somehow wandb teardown fails in `tests/test_trainer.py::TrainerIntegrationTest::test_trainer_eval_mrpc`:

```
pytest -n 1 tests/test_trainer.py::TrainerIntegrationTest::test_trainer_eval_mrpc
====================================================================== test session starts =======================================================================
platform linux -- Python 3.7.5, pytest-5.4.3, py-1.9.0, pluggy-0.13.1
rootdir: /mnt/nvme1/code/huggingface/transformers-tests-1
plugins: hypothesis-5.5.4, filter-subpackage-0.1.1, arraydiff-0.3, flaky-3.6.1, ipynb-1.1.1.dev0, cov-2.10.0, astropy-header-0.1.2, forked-1.2.0, doctestplus-0.5.0, openfiles-0.4.0, remotedata-0.3.2, xdist-1.32.0
gw0 [1]
FE                                                                                                                                                         [100%]
wandb: Waiting for W&B process to finish, PID 19525

============================================================================= ERRORS =============================================================================
_______________________________________________ ERROR at teardown of TrainerIntegrationTest.test_trainer_eval_mrpc _______________________________________________
[gw0] linux -- Python 3.7.5 /home/stas/anaconda3/envs/main/bin/python

self = <contextlib._GeneratorContextManager object at 0x7efc47610690>, type = None, value = None, traceback = None

    def __exit__(self, type, value, traceback):
        if type is None:
            try:
>               next(self.gen)
E               OSError: [Errno 29] Illegal seek

/home/stas/anaconda3/envs/main/lib/python3.7/contextlib.py:119: OSError
============================================================================ FAILURES ============================================================================
_________________________________________________________ TrainerIntegrationTest.test_trainer_eval_mrpc __________________________________________________________
[gw0] linux -- Python 3.7.5 /home/stas/anaconda3/envs/main/bin/python

self = <contextlib._GeneratorContextManager object at 0x7efc476bbd50>, type = None, value = None, traceback = None

    def __exit__(self, type, value, traceback):
        if type is None:
            try:
>               next(self.gen)
E               OSError: [Errno 29] Illegal seek

/home/stas/anaconda3/envs/main/lib/python3.7/contextlib.py:119: OSError
==================================================================== short test summary info =====================================================================
ERROR tests/test_trainer.py::TrainerIntegrationTest::test_trainer_eval_mrpc - OSError: [Errno 29] Illegal seek
FAILED tests/test_trainer.py::TrainerIntegrationTest::test_trainer_eval_mrpc - OSError: [Errno 29] Illegal seek
```

This is a possible solution, based on this solution 
https://github.com/wandb/client/issues/1138#issuecomment-654943065
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> The diff coverage is `n/a`.

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@@            Coverage Diff             @@
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  Lines       27984    26012    -1972     
==========================================
- Hits        22412    20402    -2010     
- Misses       5572     5610      +38     
```


| [Impacted Files](https://codecov.io/gh/huggingface/transformers/pull/5835?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [src/transformers/modeling\_tf\_roberta.py](https://codecov.io/gh/huggingface/transformers/pull/5835/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ190Zl9yb2JlcnRhLnB5) | `43.98% <0.00%> (-46.86%)` | :arrow_down: |
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| [src/transformers/modeling\_tf\_distilbert.py](https://codecov.io/gh/huggingface/transformers/pull/5835/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ190Zl9kaXN0aWxiZXJ0LnB5) | `64.90% <0.00%> (-32.51%)` | :arrow_down: |
| [src/transformers/trainer\_utils.py](https://codecov.io/gh/huggingface/transformers/pull/5835/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy90cmFpbmVyX3V0aWxzLnB5) | `85.71% <0.00%> (-14.29%)` | :arrow_down: |
| [src/transformers/modeling\_tf\_albert.py](https://codecov.io/gh/huggingface/transformers/pull/5835/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ190Zl9hbGJlcnQucHk=) | `76.47% <0.00%> (-11.93%)` | :arrow_down: |
| [src/transformers/modeling\_tf\_xlm.py](https://codecov.io/gh/huggingface/transformers/pull/5835/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ190Zl94bG0ucHk=) | `80.98% <0.00%> (-10.18%)` | :arrow_down: |
| [src/transformers/modeling\_reformer.py](https://codecov.io/gh/huggingface/transformers/pull/5835/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ19yZWZvcm1lci5weQ==) | `87.70% <0.00%> (-7.98%)` | :arrow_down: |
| [src/transformers/benchmark/benchmark.py](https://codecov.io/gh/huggingface/transformers/pull/5835/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9iZW5jaG1hcmsvYmVuY2htYXJrLnB5) | `74.01% <0.00%> (-7.88%)` | :arrow_down: |
| [src/transformers/tokenization\_marian.py](https://codecov.io/gh/huggingface/transformers/pull/5835/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy90b2tlbml6YXRpb25fbWFyaWFuLnB5) | `93.80% <0.00%> (-5.37%)` | :arrow_down: |
| [src/transformers/modeling\_auto.py](https://codecov.io/gh/huggingface/transformers/pull/5835/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ19hdXRvLnB5) | `74.41% <0.00%> (-4.20%)` | :arrow_down: |
| ... and [81 more](https://codecov.io/gh/huggingface/transformers/pull/5835/diff?src=pr&el=tree-more) | |

------

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<|||||>CI doesn't have wandb installed.<|||||>I get an identical issue with wandb shutdown in other places as well, e.g. when running:

```pytest examples/test_examples.py::ExamplesTests::test_run_glue```

So far the solution seems to be to disable wandb. This works:

```
WANDB_DISABLED=true pytest examples/test_examples.py::ExamplesTests::test_run_glue
```

Unless wandb integration is being tested perhaps disabling it globally will solve this everywhere?
<|||||>pinging @borisdayma in case

<|||||>The wandb cli is being updated and will have a noop mode that we can use for easier testing.
For now `WANDB_DISABLED=true` should work.<|||||>> The wandb cli is being updated and will have a noop mode that we can use for easier testing.

would it be possible to ping this issue when it happened, so that we could resolve this? Thank you very much, @borisdayma <|||||>Sounds good, I'll keep an eye on it!<|||||>Seems to have been resolved upstream (wandb) - I can no longer reproduce this problem, closing