fast_dev_run does not execute pl.LightningModule.test_step()

[jonathanking]

I may be misunderstanding something about the trainer argument fast_dev_run. When I provide fast_dev_run=1 and I add a print statement in my LightningModule's test_step function, the print statement does not appear. In addition, I can see a progress bar for my training set and validation set, but no progress bar appears for the test set.

Is fast_dev_run actually running n batches of my training set? I have passed in a DataModule to trainer.fit() that includes a test_dataloader.

[ananthsub]

fit only runs training & validation, not testing.

trainer.test runs the test_step

[jonathanking]

Thanks for your help, that makes sense. I think it's a little unclear since this gets passed to the trainer's init function, whether or not you call trainer.fit() or trainer.test().

[ananthsub]

@jonathanking I agree. I had proposed this change to clarify this: #10444

But it was considered too big of a user experience change to proceed