[Feature] UnitTests: Mocking the run_query macro to retrieve data from a given Mocked Source/Reference

[megetron3]

The macros/models are executing the run_query function, but instead of querying the database, I would like run_query to query the mocked source defined in the unit tests.
Instead of doing this in the test:

overrides:
  macros:
    run_query:
      rows:
        - { id: 1 }

I want to mock the data directly in the ref model, such as ref('model_a'), and use it with run_query.
Example Model Code:

-- model_b.sql
run_query("select * from {{ ref('model_a') }}")

OR

-- models/model_b.sql
select * from database.schema.model_a_table
where id is not null

Example Unit Test:

unit_tests:
  - name: my_unit_test
    model: model_b
    given:
      - input: ref('model_a')
        rows:
          - {id: 1}
    expect:
      rows:
        - {id: 1}

By defining the test inputs directly in the ref model, we avoid the need to override run_query using macros, providing a clearer and more maintainable testing strategy.