Feature request: run unit tests without creating the model first

[acsbendi]

Currently, when you try to run a unit test for a model without creating the model first, you get the following error message (also see this issue):

 Compilation Error in model <model-name> (<schema-path>)
  Not able to get columns for unit test '<unit-test-name>' from relation <relation-name> because the relation doesn't exist

Ideally, unit testing should be doable fully locally, but due to this requirement of the model having to be built first, it requires a lot of work to set up a fully local unit testing solution. This is because all the source data upstream of the model needs to be present in a local DB for the build to succeed, which doesn't seem to be easy with dbt seed (due to restrictions related to databases/schemas and name conflicts).

Therefore, it seems like the least cumbersome solution would be to support running the unit tests without requiring creating the model itself first.

[b-per]

Have you tried using the sql format for the given config? In that case I think that the upstream model doesn't need to exist (but people need to then provide all the columns required in the sql)

[acsbendi]

Oh yes, you're right, it does work without the model itself when I use format: sql for all inputs. I guess then maybe a small improvement could be to mention this in the docs explicitly. Thank you!