Merge pull request #276 from joellabes/test_accepted_range

New test: accepted_range

Author: Claire Carroll

README.md

@@ -418,6 +418,45 @@ An optional `quote_columns` parameter (`default=false`) can also be used if a co
         quote_columns: true
 ```
 
+
+#### accepted_range ([source](macros/schema_tests/accepted_range.sql))
+This test checks that a column's values fall inside an expected range. Any combination of `min_value` and `max_value` is allowed, and the range can be inclusive or exclusive. Provide a `where` argument to filter to specific records only. 
+
+In addition to comparisons to a scalar value, you can also compare to another column's values. Any data type that supports the `>` or `<` operators can be compared, so you could also run tests like checking that all order dates are in the past. 
+
+Usage:
+```yaml
+version: 2
+
+models:
+  - name: model_name
+    columns:
+      - name: user_id
+        tests:
+          - dbt_utils.accepted_range:
+              min_value: 0
+              inclusive: false
+      
+      - name: account_created_at
+        tests:
+          - dbt_utils.accepted_range:
+              max_value: "getdate()"
+              #inclusive is true by default
+      
+      - name: num_returned_orders
+        tests:
+          - dbt_utils.accepted_range:
+              min_value: 0
+              max_value: "num_orders"
+      
+      - name: num_web_sessions
+        tests:
+          - dbt_utils.accepted_range:
+              min_value: 0
+              inclusive: false
+              where: "num_orders > 0"
+```
+
 ---
 ### SQL helpers
 #### get_query_results_as_dict ([source](macros/sql/get_query_results_as_dict.sql))

integration_tests/data/schema_tests/data_test_accepted_range.csv

@@ -0,0 +1,3 @@
+id
+-1
+11

integration_tests/models/schema_tests/schema.yml

@@ -101,3 +101,22 @@ models:
           combination_of_columns:
             - month
             - product
+
+  - name: data_test_accepted_range
+    columns:
+      - name: id
+        tests:
+          - dbt_utils.accepted_range:
+              min_value: -1
+              max_value: 11
+              inclusive: true
+
+          - dbt_utils.accepted_range:
+              min_value: -2
+              max_value: 11.1
+              inclusive: false
+
+          - dbt_utils.accepted_range:
+              min_value: 0
+              inclusive: true
+              where: "id <> -1"

macros/schema_tests/accepted_range.sql

@@ -0,0 +1,32 @@
+{% macro test_accepted_range(model, min_value = none, max_value = none, inclusive = true, where = "true") %}
+
+{%- set column_name = kwargs.get('column_name', kwargs.get('field')) -%}
+
+with meet_condition as(
+  select {{ column_name }} 
+  from {{ model }}
+  where {{ where }}
+),
+
+validation_errors as (
+  select *
+  from meet_condition
+  where 
+    -- never true, defaults to an empty result set. Exists to ensure any combo of the `or` clauses below succeeds
+    1 = 2 
+
+  {%- if min_value is not none %}
+    -- records with a value >= min_value are permitted. The `not` flips this to find records that don't meet the rule.
+    or not {{ column_name }} > {{- "=" if inclusive }} {{ min_value }} 
+  {%- endif %}
+
+  {%- if max_value is not none %}
+    -- records with a value <= max_value are permitted. The `not` flips this to find records that don't meet the rule.
+    or not {{ column_name }} < {{- "=" if inclusive }} {{ max_value }}
+  {%- endif %}
+)
+
+select count(*)
+from validation_errors
+
+{% endmacro %}