save_dir fix for MLflowLogger + save_dir tests for others

[awaelchli]

What does this PR do?

Fixes the error "Yaml file not found" when setting the default_root_dir in Trainer to something other than the default.

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[pep8speaks]

Hello @awaelchli! Thanks for updating this PR.

• In the file pytorch_lightning/callbacks/model_checkpoint.py:

Line 243:25: W503 line break before binary operator
Line 244:25: W503 line break before binary operator

Comment last updated at 2020-07-08 02:01:49 UTC

[codecov]

Codecov Report

Merging #2502 into master will increase coverage by 0%.
The diff coverage is 96%.

@@          Coverage Diff           @@
##           master   #2502   +/-   ##
======================================
  Coverage      90%     90%           
======================================
  Files          69      69           
  Lines        5669    5676    +7     
======================================
+ Hits         5077    5087   +10     
+ Misses        592     589    -3     

[Borda]

LGTM

[williamFalcon]

@awaelchli looks great! ready to merge?

[awaelchli]

@williamFalcon while I'm at it, I'd like to add savedir tests to the remaining loggers that don' thave them yet, not much left to do.

[williamFalcon]

@Borda we need these tests since adrian has made changes that could break the other loggers. THis PR can't land without those.

[Borda]

Ok, let's do it...

[awaelchli]

@williamFalcon verified that the MLFlowLogger is also pickleable here.
WandbLogger has an issue with pytest environment at the moment, so can't include it in tests currently. Filed an issue on their github (wandb/wandb#1138). Manual testing outside pytest however showed WandbLogger pickles and restores fine.

[mergify]

This pull request is now in conflict... :(