Added ability to use expression_is_true as a column test (#313)

Tidy up Jinja

Update changelog

CHANGELOG.md

@@ -1,6 +1,7 @@
 # dbt-utils v0.6.5 (unreleased)
 ## Features
 * Add new `accepted_range` test ([#276](https:/fishtown-analytics/dbt-utils/pull/276) [@joellabes](https:/joellabes))
+* Make `expression_is_true` work as a column test (code originally in [#226](https:/fishtown-analytics/dbt-utils/pull/226/) from [@elliottohara](https:/elliottohara), merged via [#313]) 
 
 ## Fixes
 

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.

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:

macros/schema_tests/expression_is_true.sql

@@ -7,6 +7,7 @@
 {% macro default__test_expression_is_true(model, condition) %}
 
 {% set expression = kwargs.get('expression', kwargs.get('arg')) %}
+{% set column_name = kwargs.get('column_name') %}
 
 with meet_condition as (
 
@@ -18,7 +19,11 @@ validation_errors as (
  select
  *
  from meet_condition
- where not({{expression}})
+ {% if column_name is none %}
+ where not({{ expression }})
+ {%- else %}
+ where not({{ column_name }} {{ expression }})
+ {%- endif %}
 
 )