Add a new macro to test numeric types with specific precision and scale

[samousavih]

Issue this PR Addresses/Closes

Closes #(262)

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Summary of Changes

1. A new macro to assert numeric types and their scale and precision

Why Do We Need These Changes

Current macro to assert column types doesn't include scale and precision.

Reviewers

@clausherther

[clausherther]

Hi, sorry for the delayed response! Instead of making a new test, would it be possible to make this an optional path in expect_column_values_to_be_of_type?

(FYI, BigQuery fails on this test.)

[samousavih]

Hey @clausherthe, thanks for the reply,
One option is to make 'expect_column_values_to_be_of_type' and 'expect_column_values_to_be_in_type_list' assert precision and scale when mentioned and ignore them when not, which is potentially what most would expect from the test.

- dbt_expectations.expect_column_values_to_be_of_type:
      column_type: numeric(2,1)
- dbt_expectations.expect_column_values_to_be_in_type_list:
      column_type_list: [numeric(2,1)]

- dbt_expectations.expect_column_values_to_be_of_type:
      column_type: numeric
- dbt_expectations.expect_column_values_to_be_in_type_list:
      column_type_list: [numeric]

How does this look like to you?
Only minor issue might be it could fail existing tests once package users upgrade, which could be a good thing depending how you look at it.