Play with test_metadata.kwargs

.changes/unreleased/Features-20220427-095609.yaml

@@ -0,0 +1,7 @@
+kind: Features
+body: Add support for percentages in error_if, warn_if
+time: 2022-04-27T09:56:09.707636+10:00
+custom:
+  Author: jaypeedevlin ehmartens
+  Issue: "4723"
+  PR: "5172"

core/dbt/clients/jinja.py

@@ -630,5 +630,7 @@ def add_rendered_test_kwargs(
 
     # The test_metadata.kwargs come from the test builder, and were set
     # when the test node was created in _parse_generic_test.
+    # Overwrite them with the rendered versions during test compilation
     kwargs = deep_map_render(_convert_function, node.test_metadata.kwargs)
+    node.test_metadata.kwargs = kwargs
     context[GENERIC_TEST_KWARGS_NAME] = kwargs

core/dbt/include/global_project/macros/materializations/tests/helpers.sql

@@ -3,12 +3,27 @@
 {%- endmacro %}
 
 {% macro default__get_test_sql(main_sql, fail_calc, warn_if, error_if, limit) -%}
+    {% set model_name = model.test_metadata.kwargs.model %}
+    {% set warn_if, warn_pct_division = get_pct_division(warn_if, model_name) %}
+    {% set error_if, error_pct_division = get_pct_division(error_if, model_name) %}
+
     select
       {{ fail_calc }} as failures,
-      {{ fail_calc }} {{ warn_if }} as should_warn,
-      {{ fail_calc }} {{ error_if }} as should_error
+      {{ fail_calc }} {{ warn_pct_division }} {{ warn_if }} as should_warn,
+      {{ fail_calc }} {{ error_pct_division }} {{ error_if }} as should_error
     from (
       {{ main_sql }}
       {{ "limit " ~ limit if limit != none }}
     ) dbt_internal_test
 {%- endmacro %}
+
+
+{% macro get_pct_division(threshold, model_name) %}
+  {% if threshold[-1] == '%' %}
+    {% set threshold = threshold[:-1] %}
+    {% set pct_division = '/ (select count(*) from ' ~ ref(model_name) ~ ') * 100' %}
+  {% else %}
+    {% set pct_division = '' %}
+  {% endif %}
+    {% do return((threshold, pct_division)) %}
+{% endmacro %}