simplify shimming

[dataders]

high-level summary

• refactored get_test_dates() in order to:
  • more surgically change behavior, and
  • keep shimmed macros more in line w/ dbt-date's integration tests as they update.
• deleted dbt_date_integration_tests's _get_utils_namespaces() to align with dbt-utils's strategy of joining integration test macros to the dispatch list. (note: this will certainly change with v0.20.0, but at least it's a step in the right direction.

detail

resolves: #25
given that the only difference in get_test_dates() is the week_of_year column, this will make it easier to shim.

once this merges, making get_test_dates() working for TSQL will be as simple as adding this macro to the tsql-utils dbt-date integration tests macros folder (see: dbt-msft/tsql-utils#48)

{% macro sqlserver__get_test_week_of_year() -%}
    {{ log("in the right macro!", info=True) }}
    {# who knows what T-SQL uses?! #}
    {# see: https://github.com/calogica/dbt-date/issues/25 #}
    {{ return([49,49]) }}
{%- endmacro %}

{% macro synapse__get_test_week_of_year() -%}
     {{ return(sqlserver__get_test_week_of_year()) }}
{%- endmacro %}

[clausherther]

👍

[clausherther]

I think this works for now, although this seems a bit harder to follow for anyone new than simply having a separate test dataset for each platform.