Describe the bug

I would like to limit the rows compared in dbt_utils.equality test with a where clause.

Steps to reproduce

Create two models with the same set of columns. Configure equality test with where configuration - in this case a date limitation.

`
version: 2

models:

• name: model_v2
  tests:
  • dbt_utils.equality:
    compare_model: ref('model_v1')
    where: "dt_date > DATE_ADD(current_date('Europe/Stockholm'), INTERVAL -1 DAY)"
    `

Expected results

The equality test executed with the where clause added to both "model" and "compare_model".

Actual results

Compilation error

Screenshots and log output

Compilation Error in test dbt_utils_equality_model_v2_ref_model_v1_ (models/model_v2.yml)
11:48:56 Macro test_equality expected a Relation but received the value: (select * from project.dataset.model_v2 where dt_date > DATE_ADD(current_date('Europe/Stockholm'), INTERVAL -1 DAY)) dbt_subquery
11:48:56
11:48:56 > in macro _is_relation (macros/cross_db_utils/_is_relation.sql)
11:48:56 > called by macro default__test_equality (macros/generic_tests/equality.sql)
11:48:56 > called by macro test_equality (macros/generic_tests/equality.sql)

System information

The contents of your packages.yml file:
packages:

• package: dbt-labs/dbt_utils
  version: 0.8.6
• package: mjirv/dbt_datamocktool
  version: 0.2.0

Which database are you using dbt with?

• postgres
• redshift
• bigquery
• snowflake
• other (specify: ____________)

The output of dbt --version:

Core:
  - installed: 1.1.1
  - latest:    1.3.0 - Update available!

  Your version of dbt-core is out of date!
  You can find instructions for upgrading here:
  https://docs.getdbt.com/docs/installation

Plugins:
  - bigquery: 1.1.1 - Update available!

  At least one plugin is out of date or incompatible with dbt-core.
  You can find instructions for upgrading here:
  https://docs.getdbt.com/docs/installation

Additional context

It seems the check not working is https://github.com/dbt-labs/dbt-utils/blob/main/macros/generic_tests/equality.sql#L23

My understanding of the check is to make sure of the later use of adapter.get_columns_in_relation will work.

My guess is that the most important part that the where config is added is in the CTEs named a and b.

Are you interested in contributing the fix?

Sure - would be great with some hints on where to start