[Bigquery] unit test tests + support for complex types

[MichelleArk]

resolves #1090
docs dbt-labs/docs.getdbt.com/#

Problem

Solution

• Adds test implementations for base tests around unit testing
• expands coverage for safe_cast macro.

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

[github-actions]

Thank you for your pull request! We could not find a changelog entry for this change. For details on how to document a change, see the dbt-bigquery contributing guide.

[github-christophe-oudar]

Quick question, are the STRUCTs supported? If not, is planned as well? Thanks!

[MichelleArk]

@github-christophe-oudar - sorry for the delayed response but short answer is - yes!

🎩 @jtcohen6 and I were just tophatting the syntax today! Here's an example:

-- models/test_my_model.sql
unit_tests:
  - name: test_my_model
    model: model_b
    given:
      - input: ref('model_a')
        rows:
          - my_field: 'struct(1 as id, "bleu" as color)'
    expect:
      rows:
        - my_field: 'struct(1 as id, "blanc&rouge" as color)'

& here are the logs for a failed test!

[MichelleArk]

Failing test looks unrelated: https://github.com/dbt-labs/dbt-bigquery/actions/runs/7807239952/job/21295234626?pr=1031

Should be fixed by: dbt-labs/dbt-common#69

[github-christophe-oudar]

@MichelleArk, great! I saw the commit yesterday 🚀
I'm watching the PR and I'll test it once it's merged on the main branch 👍 (maybe before locally if I find some time to tinker)

[github-christophe-oudar]

Just wanted a quick follow up here to say that we're already using unit tests in production beside for the models using UDFs.
My coworker will soon release an article about our usage 👍

[martynydbt]

Looking forward to reading it! @github-christophe-oudar Thank you for sharing!