Select models which have tests with additional dependencies

[adammarples]

Description

Tests such as the relationship test will fail to be selected if we are selecting models with tags and using the manifest loading method.

Related Issue(s)

closes #719

Breaking Change?

Almost all tests will have only one 'depends_on', but when they have two, ie. relationship, the true parent is the last one.

load_from_dbt_manifest now considers the primary selectable parent model of a test to be the last item in its 'depends_on' list, rather than the first.

This would break any tests being loaded by tag selection using load_from_dbt_manifest which somehow depended on a model being the first in that list rather than the last.

Checklist

• [ ] I have made corresponding changes to the documentation (if required)
• [x] I have added tests that prove my fix is effective or that my feature works

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[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (82e8db9) 93.27% compared to head (6c4bfe4) 93.28%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #751      +/-   ##
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+ Coverage   93.27%   93.28%   +0.01%     
==========================================
  Files          55       55              
  Lines        2499     2503       +4     
==========================================
+ Hits         2331     2335       +4     
  Misses        168      168              

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[ms32035]

@adammarples as you're working on this, I'd like to bring to your attention a case you're missing, and which we're running into recently:

  File "/home/airflow/.local/lib/python3.11/site-packages/cosmos/dbt/selector.py", line 298, in _should_include_node
    node.tags = getattr(self.nodes.get(node.depends_on[0]), "tags", [])
                                       ~~~~~~~~~~~~~~~^^^
IndexError: list index out of range

Although not a dbt best practice, it's entirely possible to have a test with 0 dependencies, or model dependencies (test on sources)

[tatiana]

Hi @adammarples , this PR - and the discussion - was beneficial. Thank you. And thanks, @jbandoro, for giving an alternative solution to the problem.

Cosmos can improve its implementation towards tests with multiple parents - we should make it consistent with dbt. @adammarples, you make a great start - would you be interested in further contributing to this - or would you rather close this PR and let someone else take over the work?

@ms32035 I didn't realise that was possible! Although it relates to the original problem, I logged a separate ticket: #782. Would you be interested in contributing?

[tatiana]

Closing this PR in favour of the ticket: https://github.com/astronomer/astronomer-cosmos/issues/978