Remove dbt-postgres and dbt-tests-adapter from dbt-core

[colin-rogers-dbt]

Remove dbt-tests-adapter and dbt-postgres from dbt-core but preserve the adapter one tests in the functional directory to make sure we don't lose any test coverage.

resolves #

Problem

Solution

Checklist

• I have read the contributing guide and understand what's expected of me
• I have run this code in development and it appears to resolve the stated issue
• This PR includes tests, or tests are not required/relevant for this PR
• This PR has no interface changes (e.g. macros, cli, logs, json artifacts, config files, adapter interface, etc) or this PR has already received feedback and approval from Product or DX
• This PR includes type annotations for new and modified functions

[github-actions]

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (1a5d692) 88.04% compared to head (db779c4) 87.85%.
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #9492      +/-   ##
==========================================
- Coverage   88.04%   87.85%   -0.20%     
==========================================
  Files         167      167              
  Lines       22126    22150      +24     
==========================================
- Hits        19480    19459      -21     
- Misses       2646     2691      +45     

Flag	Coverage Δ
integration	85.44% <ø> (-0.15%)	⬇️
unit	61.85% <ø> (-0.51%)	⬇️

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[emmyoop]

Have you tested if the release will work without any changes?

[emmyoop]

Is the postgres repo going to have the ability to run tests off branches of core?

[colin-rogers-dbt]

indeed it will

[MichelleArk]

In theory, the dbt-postgres tests shouldn't provide us with additional testing signal on dbt-core changes that we wouldn't be able to pick up in our existing functional tests. But the current state of things is less ideal than that 🙃

For example, test_dbt_show tests adapter-specific functionality, but I don't see another test in tests/functional that includes the --limit argument.

We can't really know the full extent of this without auditing all the tests but we'll definitely lose test coverage by removing them outright at this point, so I agree with the decision to keep them + move to tests/functional.

My main concern is that these will drift from their source definitions in dbt-adapters/dbt-postgres over time as new tests are defined in those directories. Longer term, we should explore options for running the postgres tests on commit / before merge without having to actually define them in dbt-core.

[colin-rogers-dbt]

Have you tested if the release will work without any changes?

@emmyoop testing here: https://github.com/dbt-labs/dbt-core/actions/runs/7759825156/job/21164841687

[MichelleArk]

Added a follow-on tech debt issue for dbt-core to delete the adapter tests entirely, and instead trigger dbt-postgres adapter tests to run: #9513