Unit testing docs

[dbeatty10]

Contributions

• I have read the contribution docs, and understand what's expected of me.

Link to the page on docs.getdbt.com requiring updates

https://docs.getdbt.com/docs/build/unit-tests

What part(s) of the page would you like to see updated?

We got some feedback that suggested the following updates to our documentation:

• Clarify fixture requirements for all dependencies (to avoid null values in output)
• Emphasize satisfying all model logic conditions (i.e. join / where clauses to avoid nulls)
• Under-the-hood code example of how unit tests compile

Additional information

No response

[runleonarun]

Thanks Doug! Let us know when you want a review on that PR.

[grindheim]

I'm not sure if this might at all be relevant, but I found (in my opinion) a setup for using unit tests for macros that seem to work pretty well, and might be especially relevant for package maintainers.
So just putting it out there in case you'd like to modify this point slightly: We currently only support unit testing SQL models.
https://medium.com/p/89bdb5de8634