Use boolean for zero range arg.

README.md

@@ -394,17 +394,17 @@ the lower bound of the next record (common for date ranges).
 | 2           | 3           |
 | 4           | 5           |
 
-**Understanding the `zero_length` parameter:**
-Here are a number of examples for each allowed `zero_length` parameter.
-* `zero_length:not_allowed`: The upper bound of each record must be greater than its lower bound.
+**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:allowed`: The upper bound of each record can be greater than or equal to its lower bound.
+* `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 |
 |-------------|-------------|

integration_tests/models/schema_tests/schema.yml

@@ -101,7 +101,7 @@ models:
           lower_bound_column: valid_from
           upper_bound_column: valid_to
           partition_by: subscription_id
-          zero_length: allowed
+          zero_length_range_allowed: true
 
   - name: data_unique_combination_of_columns
     tests:

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', zero_length='not_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='=' %}
@@ -14,15 +14,15 @@
         "`gaps` argument for mutually_exclusive_ranges test must be one of ['not_allowed', 'allowed', 'required'] Got: '" ~ gaps ~"'.'"
     ) }}
 {% endif %}
-{% if zero_length == 'not_allowed' %}
+{% if not zero_length_range_allowed %}
     {% set allow_zero_length_operator='<' %}
     {% set allow_zero_length_operator_in_words='less_than' %}
-{% elif zero_length == 'allowed' %}
+{% 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` argument for mutually_exclusive_ranges test must be one of ['not_allowed', 'allowed'] Got: '" ~ zero_length ~"'.'"
+        "`zero_length_range_allowed` argument for mutually_exclusive_ranges test must be one of [true, false] Got: '" ~ zero_length ~"'.'"
     ) }}
 {% endif %}