diff: model.shop.dim_customers  kept=2  kept-uncertain=1  dropped=1  flagged=1

TIER            ARTIFACT                      TEST            REASON                  SCORE    WHY
kept            column.customer_id.descript…                                          0.85     Description added; passed all grading criteria.
kept            test.column.customer_id.not…  not_null                                —        Test returned non-zero failing rows on the warehouse sample.
kept-uncertain  test.column.email.unique      unique                                  —        total prune budget exceeded before evaluation
dropped         test.column.customer_id.uni…  unique          always-passes           —        Test returned zero failing rows on the representative sample.
flagged         column.email.description                                              0.45     Grading score 0.45 below threshold 0.50.

--- a/models/dim_customers.yml
+++ b/models/dim_customers.yml
@@ -1,5 +1,8 @@
 version: 2
 models:
   - name: dim_customers
     columns:
       - name: customer_id
+        description: Surrogate key.
+        tests:
+          - not_null