Fix for missing intent warnings when running rasa test

[b-quachtran]

Proposed changes:

• Fix for missing intent warnings when running rasa test
• Closes issue Rasa test/rasa test core can't find any intent in domain #8135

Status (please check what you already did):

• added some tests for the functionality
• updated the documentation
• updated the changelog (please check changelog for instructions)
• reformat files using black (please check Readme for instructions)

[m-vdb]

@b-quachtran thanks for pushing fix -- should we ask someone from Enable to review this PR?

[b-quachtran]

Hey @m-vdb, yes definitely. I still need to wrap up a few things in this PR related to test cases, but will tag Enable as soon as it's ready.

[joejuzl]

Nice one 👍
Is there an easy to test this is fixed with a unit test?

[b-quachtran]

@joejuzl Yep, I'll add a unit test as well 👍

[nearlyhuman-jwheat]

I've just updated to the recent release of 2.7.0 and the first thing I did was check to see if this issue was fixed.

I ran

rasa test --stories tests/test_stories.yml --fail-on-prediction-errors

And it can't find my domain.yml files.

/home/jwheat/anaconda2/envs/rasa263/lib/python3.7/site-packages/rasa/shared/utils/io.py:97: UserWarning: Loading domain from 'domain.yml' failed. Using empty domain. Error: 'Failed to load domain specification from '/mnt/d/Code/NearlyHuman/RASA2/rasa-demo-server/domain.yml'. File not found!'

I admit I have a more robust directory structure, but when I train I add --domain data and it finds them all, however rasa test doesn't accept that flag, so I get screens of

/home/jwheat/anaconda2/envs/rasa263/lib/python3.7/site-packages/rasa/shared/utils/io.py:97: UserWarning: Issue found in 'data/general-support/stories.yml':    
Found intent 'affirm' in stories which is not part of the domain.

More importantly, all my test stories fail, I'm guessing because it can't find my domain.yml files.

FWIW my structure looks like this where I have individual "skills" broken out into their own directory structure.

data/
    /skill1/
           domain.yml
           rules.yml
           nlu.yml
           stories.yml
    /skill2/
           domain.yml
           rules.yml
           nlu.yml
           stories.yml
etc.

I have no files in the root of my data directory and it looks like that's where this version is looking based on the first UserWarning.

Is there any way to get rasa test to see my structure and act like rasa train does with a --domain data flag?

Also curious what it does with the training data itself. Shouldn't rasa test only use the pre-trained model? Why does it need to look at all the domain files?