wand module not found when running test_mlm.py

[josemlopez]

How to reproduce

python ./tests/transformers/models/electra/test_mlm.py

Environment

• OS : CentOS 7.9
• Python version : 3.9
• Transformers version : 4.21.2
• Whether to use Docker:
• Misc.:

python ./tests/transformers/models/electra/test_mlm.py 
Traceback (most recent call last):
  File "./tests/transformers/models/electra/test_mlm.py", line 8, in <module>
    import wandb
ModuleNotFoundError: No module named 'wandb'

I'm using an empty box for these tests and wandb is not installed here. If wandb is a needed library should it be included in the setup.py?

[hyunwoongko]

thanks for making a great issue wandb is using only for test. so I thought it's unnecessary as requirements. after we finished all the works for oslo 2.1, we should refine all the test scripts.