From 0cd7ade90ee8b33915505e41b59b8089c40a510f Mon Sep 17 00:00:00 2001
From: Elliott O'Hara <elliott.ohara@getupside.com>
Date: Thu, 4 Jun 2020 10:20:48 -0500
Subject: [PATCH] Added ability to use expression_is_true as a column test

---
 README.md                                     | 19 +++++++++++++++++++
 .../models/schema_tests/schema.yml            | 10 ++++++++++
 macros/schema_tests/expression_is_true.sql    |  3 ++-
 3 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 7bd4a1c2..514c1bc2 100644
--- a/README.md
+++ b/README.md
@@ -181,6 +181,25 @@ models:
 
 ```
 
+This macro can also be used at the column level. When this is done, the `expression` is evaluated against the column.  
+
+```yaml
+version: 2
+models: 
+    - name: model_name
+      columns: 
+        - name: col_a
+          tests:
+            - dbt_utils.expression_is_true:
+                expression: '>= 1'
+        - name: col_b
+          tests:
+            - dbt_utils.expression_is_true:
+                expression: '= 1'
+                condition: col_a = 1
+      
+```
+
 
 #### recency ([source](macros/schema_tests/recency.sql))
 This schema test asserts that there is data in the referenced model at least as recent as the defined interval prior to the current timestamp.
diff --git a/integration_tests/models/schema_tests/schema.yml b/integration_tests/models/schema_tests/schema.yml
index 0026b957..cbc9cff9 100644
--- a/integration_tests/models/schema_tests/schema.yml
+++ b/integration_tests/models/schema_tests/schema.yml
@@ -20,6 +20,16 @@ models:
       - dbt_utils.expression_is_true:
           expression: col_a = 0.5
           condition: col_b = 0.5
+    columns:
+      - name: col_a
+        tests:
+          - dbt_utils.expression_is_true:
+              expression: + col_b = 1
+      - name: col_b
+        tests:
+          - dbt_utils.expression_is_true:
+              expression: = 0.5
+              condition: col_a = 0.5
 
   - name: test_recency
     tests:
diff --git a/macros/schema_tests/expression_is_true.sql b/macros/schema_tests/expression_is_true.sql
index 5ff9c334..5c1abc8e 100644
--- a/macros/schema_tests/expression_is_true.sql
+++ b/macros/schema_tests/expression_is_true.sql
@@ -1,6 +1,7 @@
 {% macro test_expression_is_true(model, condition='true') %}
 
 {% set expression = kwargs.get('expression', kwargs.get('arg')) %}
+{% set column_name = kwargs.get('column_name') %}
 
 with meet_condition as (
 
@@ -12,7 +13,7 @@ validation_errors as (
     select
         *
     from meet_condition
-    where not({{expression}})
+    where not( {{ expression if column_name is none else [column_name, expression] | join(' ')  }})
 
 )