chore: add comments to explain structure of test macros

macros/generic_tests/test_exists.sql

@@ -3,12 +3,14 @@
 {# Test fails if 0 records are returned. #}
 {{ config(fail_calc = 'case when count(*) = 0 then 1 else 0 end') }}
 
+{# Query the column in INFORMATION_SCHEMA to check if it exists. #}
 select *
 from "INFORMATION_SCHEMA"."COLUMNS"
 where "INFORMATION_SCHEMA"."COLUMNS"."TABLE_SCHEMA" = '{{ model.schema }}'
     and "INFORMATION_SCHEMA"."COLUMNS"."TABLE_NAME" = '{{ model.name }}'
     and "INFORMATION_SCHEMA"."COLUMNS"."COLUMN_NAME" = replace('{{ column_name }}', '"', '')
 
+{# Query to get the record count when executing the test. #}
 {% set query %}
     select count(*) as "test_record_count"
     from "INFORMATION_SCHEMA"."COLUMNS"

macros/generic_tests/test_field_length.sql

@@ -1,5 +1,6 @@
 {% macro test_field_length(model, column_name, length) %}
 
+{# Get columns in the relation to check if the field exists. #}
 {%- set columns = adapter.get_columns_in_relation(model) -%}
 
 {%- set column_names = [] -%}
@@ -9,10 +10,12 @@
 
 {# Only execute test when field exists. Otherwise execute a dummy test that always succeeds. #}
 {% if column_name in column_names %}
+    {# Query the records that fail the test. #}
     select {{ column_name }}
     from {{ model }}
     where len({{ column_name }}) <> {{ length }}
 
+    {# Query to get the record count when executing the test. #}
     {% set query %}
         select count(*) as "test_record_count"
         from {{ model }}

macros/generic_tests/test_format.sql

@@ -1,7 +1,9 @@
 {% macro test_format(model, column_name, data_type) %}
 
+{# Test fails if the difference in number of null values before and after data type casting is different. #}
 {{ config(fail_calc = 'coalesce("diff_count", 0)') }}
 
+{# Get columns in the relation to check if the field exists. #}
 {%- set columns = adapter.get_columns_in_relation(model) -%}
 
 {%- set column_names = [] -%}
@@ -11,6 +13,7 @@
 
 {# Only execute test when field exists. Otherwise execute a dummy test that always succeeds. #}
 {% if column_name in column_names %}
+    {# Query to get the difference in number of null values. #}
     {% set query %}
         select
             abs(count_before_casting - count_after_casting) as "diff_count"

macros/generic_tests/test_not_null.sql

@@ -1,5 +1,6 @@
 {% macro test_not_null(model, column_name) %}
 
+{# Get columns in the relation to check if the field exists. #}
 {%- set columns = adapter.get_columns_in_relation(model) -%}
 
 {%- set column_names = [] -%}
@@ -9,10 +10,12 @@
 
 {# Only execute test when field exists. Otherwise execute a dummy test that always succeeds. #}
 {% if column_name in column_names %}
+    {# Query the records that fail the test. #}
     select {{ column_name }}
     from {{ model }}
     where {{ column_name }} is null
 
+    {# Query to get the record count when executing the test. #}
     {% set query %}
         select count(*) as "test_record_count"
         from {{ model }}

macros/generic_tests/test_one_column_not_null.sql

@@ -1,5 +1,6 @@
 {% macro test_one_column_not_null(model, columns) %}
 
+{# Get columns in the relation to check if the fields exist. #}
 {%- set columns_in_relation = adapter.get_columns_in_relation(model) -%}
 
 {%- set column_names = [] -%}
@@ -23,10 +24,12 @@
     {% endfor %}
     {% set calculation = column_list | join('\n    + ') %}
 
+    {# Query the records that fail the test. #}
     select *
     from {{ model }}
     where {{ calculation }} <> 1
 
+    {# Query to get the record count when executing the test. #}
     {% set query %}
         select count(*) as "test_record_count"
         from {{ model }}

macros/generic_tests/test_unique.sql

@@ -1,5 +1,6 @@
 {% macro test_unique(model, column_name) %}
 
+{# Get columns in the relation to check if the field exists. #}
 {%- set columns = adapter.get_columns_in_relation(model) -%}
 
 {%- set column_names = [] -%}
@@ -9,11 +10,13 @@
 
 {# Only execute test when field exists. Otherwise execute a dummy test that always succeeds. #}
 {% if column_name in column_names %}
+    {# Query the records that fail the test. #}
     select {{ column_name }}
     from {{ model }}
     group by {{ column_name }}
     having count(*) > 1
 
+    {# Query to get the record count when executing the test. #}
     {% set query %}
         select count(*) as "test_record_count"
         from (

macros/generic_tests/test_unique_combination_of_columns.sql

@@ -1,5 +1,6 @@
 {% macro test_unique_combination_of_columns(model, combination_of_columns) %}
 
+{# Get columns in the relation to check if the fields exist. #}
 {%- set columns_in_relation = adapter.get_columns_in_relation(model) -%}
 
 {%- set column_names = [] -%}
@@ -24,11 +25,13 @@
 
     {% set columns_csv = column_list | join(', ') %}
 
+    {# Query the records that fail the test. #}
     select {{ columns_csv }}
     from {{ model }}
     group by {{ columns_csv }}
     having count(*) > 1
 
+    {# Query to get the record count when executing the test. #}
     {% set query %}
         select count(*) as "test_record_count"
         from (