Merge pull request #307 from zemekeneng/feature/exclusive_ranges_with_gaps_zero_length

Add zero length option to exclusive range test.

Author: Claire Carroll

README.md

@@ -361,6 +361,15 @@ models:
           upper_bound_column: ended_at
           partition_by: customer_id
           gaps: required
+  
+  # test that each customer can have subscriptions that start and end on the same date
+  - name: subscriptions
+    tests:
+      - dbt_utils.mutually_exclusive_ranges:
+          lower_bound_column: started_at
+          upper_bound_column: ended_at
+          partition_by: customer_id
+          zero_length: allowed
 ```
 **Args:**
 * `lower_bound_column` (required): The name of the column that represents the
@@ -372,6 +381,8 @@ upper value of the range. Must be not null.
 argument to indicate which column to partition by. `default=none`
 * `gaps` (optional): Whether there can be gaps are allowed between ranges.
 `default='allowed', one_of=['not_allowed', 'allowed', 'required']`
+* `zero_length` (optional): Whether ranges can start and end on the same date.
+`default='not_allowed', one_of=['not_allowed', 'allowed']`
 
 **Note:** Both `lower_bound_column` and `upper_bound_column` should be not null.
 If this is not the case in your data source, consider passing a coalesce function
@@ -418,6 +429,24 @@ the lower bound of the next record (common for date ranges).
 | 2           | 3           |
 | 4           | 5           |
 
+**Understanding the `zero_length_range_allowed` parameter:**
+Here are a number of examples for each allowed `zero_length_range_allowed` parameter.
+* `zero_length_range_allowed:false`: (default) The upper bound of each record must be greater than its lower bound.
+
+| lower_bound | upper_bound |
+|-------------|-------------|
+| 0           | 1           |
+| 1           | 2           |
+| 2           | 3           |
+
+* `zero_length_range_allowed:true`: The upper bound of each record can be greater than or equal to its lower bound.
+
+| lower_bound | upper_bound |
+|-------------|-------------|
+| 0           | 1           |
+| 2           | 2           |
+| 3           | 4           |
+
 #### unique_combination_of_columns ([source](macros/schema_tests/unique_combination_of_columns.sql))
 This test confirms that the combination of columns is unique. For example, the
 combination of month and product is unique, however neither column is unique

integration_tests/data/schema_tests/data_test_mutually_exclusive_ranges_with_gaps_zero_length.csv

@@ -0,0 +1,7 @@
+subscription_id,valid_from,valid_to
+3,2020-05-06,2020-05-07
+3,2020-05-08,2020-05-08
+3,2020-05-09,2020-05-10
+4,2020-06-06,2020-06-07
+4,2020-06-08,2020-06-08
+4,2020-06-09,2020-06-10

integration_tests/models/schema_tests/schema.yml

@@ -112,6 +112,14 @@ models:
           partition_by: subscription_id
           gaps: required
 
+  - name: data_test_mutually_exclusive_ranges_with_gaps_zero_length
+    tests:
+      - dbt_utils.mutually_exclusive_ranges:
+          lower_bound_column: valid_from
+          upper_bound_column: valid_to
+          partition_by: subscription_id
+          zero_length_range_allowed: true
+ 
   - name: data_unique_combination_of_columns
     tests:
       - dbt_utils.unique_combination_of_columns:

macros/schema_tests/mutually_exclusive_ranges.sql

@@ -1,4 +1,4 @@
-{% macro test_mutually_exclusive_ranges(model, lower_bound_column, upper_bound_column, partition_by=None, gaps='allowed') %}
+{% macro test_mutually_exclusive_ranges(model, lower_bound_column, upper_bound_column, partition_by=None, gaps='allowed', zero_length_range_allowed=False) %}
 
 {% if gaps == 'not_allowed' %}
     {% set allow_gaps_operator='=' %}
@@ -13,7 +13,17 @@
     {{ exceptions.raise_compiler_error(
         "`gaps` argument for mutually_exclusive_ranges test must be one of ['not_allowed', 'allowed', 'required'] Got: '" ~ gaps ~"'.'"
     ) }}
-
+{% endif %}
+{% if not zero_length_range_allowed %}
+    {% set allow_zero_length_operator='<' %}
+    {% set allow_zero_length_operator_in_words='less_than' %}
+{% elif zero_length_range_allowed %}
+    {% set allow_zero_length_operator='<=' %}
+    {% set allow_zero_length_operator_in_words='less_than_or_equal_to' %}
+{% else %}
+    {{ exceptions.raise_compiler_error(
+        "`zero_length_range_allowed` argument for mutually_exclusive_ranges test must be one of [true, false] Got: '" ~ zero_length ~"'.'"
+    ) }}
 {% endif %}
 
 {% set partition_clause="partition by " ~ partition_by if partition_by else '' %}
@@ -51,9 +61,9 @@ calc as (
         -- Coalesce it to return an error on the null case (implicit assumption
         -- these columns are not_null)
         coalesce(
-            lower_bound < upper_bound,
+            lower_bound {{ allow_zero_length_operator }} upper_bound,
             false
-        ) as lower_bound_less_than_upper_bound,
+        ) as lower_bound_{{ allow_zero_length_operator_in_words }}_upper_bound,
 
         -- For each record: upper_bound {{ allow_gaps_operator }} the next lower_bound.
         -- Coalesce it to handle null cases for the last record.
@@ -75,7 +85,7 @@ validation_errors as (
 
     where not(
         -- THE FOLLOWING SHOULD BE TRUE --
-        lower_bound_less_than_upper_bound
+        lower_bound_{{ allow_zero_length_operator_in_words }}_upper_bound
         and upper_bound_{{ allow_gaps_operator_in_words }}_next_lower_bound
     )
 )