Migrate current integration tests to pytest

[dave-connors-3]

Describe the feature

In order to mirror the approach of dbt core as well as the rest of the package ecosystem, we should consider moving our test suite to pytest. This also gives us more flexibility to add test scenarios without having to maintain multiple dbt projects with specific characteristics of interest (i.e. integration_tests vs integration_tests_2)

Describe alternatives you've considered

Continuing to use nested dbt projects

Who will this benefit?

Developers and maintainers!

Are you interested in contributing this feature?

Certainly part of it!

[b-per]

@dave-connors-3 , do you have a list of repos that use pytest today instead of an integration_tests project? dbt-core is doing it but I checked quickly dbt-utils and it looks like it hasn't moved to pytest yet (and personally that would be the one I would try to replicate from)

[dave-connors-3]

utils should have some, but these may just be ported over from core as they migrated the cross db utils.

Metrics also has pytest based testing