Fix the unit test materialization so that it finds columns in the quoted column mapping (#1274)

Author: QMalcolm

dbt-adapters/.changes/unreleased/Fixes-20250818-174217.yaml

@@ -0,0 +1,6 @@
+kind: Fixes
+body: Correct column mapping lookup in unit test macro
+time: 2025-08-18T17:42:17.687393-05:00
+custom:
+  Author: QMalcolm
+  Issue: "1273"

dbt-adapters/src/dbt/include/global_project/macros/materializations/tests/unit.sql

@@ -19,7 +19,7 @@
 
   {%- set expected_column_names_quoted = [] -%}
   {%- for column_name in tested_expected_column_names -%}
-  {%-   do expected_column_names_quoted.append(column_name_to_quoted[column_name]) -%}
+  {%-   do expected_column_names_quoted.append(column_name_to_quoted[column_name|lower]) -%}
   {%- endfor -%}
 
   {% if not expected_sql %}

dbt-postgres/tests/functional/adapter/test_unit_testing.py

@@ -1,5 +1,8 @@
 from dbt.tests.adapter.unit_testing.test_case_insensitivity import BaseUnitTestCaseInsensivity
 from dbt.tests.adapter.unit_testing.test_invalid_input import BaseUnitTestInvalidInput
+from dbt.tests.adapter.unit_testing.test_quoted_reserved_word_column_names import (
+    BaseUnitTestQuotedReservedWordColumnNames,
+)
 from dbt.tests.adapter.unit_testing.test_types import BaseUnitTestingTypes
 
 
@@ -13,3 +16,7 @@ class TestPostgresUnitTestInvalidInput(BaseUnitTestInvalidInput):
 
 class TestPostgresUnitTestingTypes(BaseUnitTestingTypes):
     pass
+
+
+class TestPostgresUnitTestQuotedReservedWordColumnNames(BaseUnitTestQuotedReservedWordColumnNames):
+    pass

dbt-tests-adapter/.changes/unreleased/Features-20250818-181937.yaml

@@ -0,0 +1,7 @@
+kind: Features
+body: Add new test for test unit tests involing models with columns with reserved
+  words
+time: 2025-08-18T18:19:37.508909-05:00
+custom:
+  Author: QMalcolm
+  Issue: "1273"

dbt-tests-adapter/src/dbt/tests/adapter/unit_testing/test_quoted_reserved_word_column_names.py

@@ -0,0 +1,64 @@
+import pytest
+from dbt.tests.util import run_dbt
+
+
+my_model_sql = """
+select
+    * from {{ ref('my_upstream_model')}}
+"""
+
+my_upstream_model_with_reserved_word_column_name_sql = """
+select 1 as "GROUP"
+"""
+
+test_my_model_csv_fixtures_yml = """
+unit_tests:
+  - name: test_my_model
+    model: my_model
+    given:
+      - input: ref('my_upstream_model')
+        format: csv
+        fixture: input_fixture
+    expect:
+      format: csv
+      fixture: expect_fixture
+"""
+
+input_fixture_csv = """
+GROUP
+1
+2
+3
+"""
+
+expect_fixture_csv = """
+GROUP
+1
+2
+3
+"""
+
+
+class BaseUnitTestQuotedReservedWordColumnNames:
+    @pytest.fixture(scope="class")
+    def models(self):
+        return {
+            "my_model.sql": my_model_sql,
+            "my_upstream_model.sql": my_upstream_model_with_reserved_word_column_name_sql,
+            "unit_tests.yml": test_my_model_csv_fixtures_yml,
+        }
+
+    @pytest.fixture(scope="class")
+    def tests(self):
+        return {
+            "fixtures": {
+                "input_fixture.csv": input_fixture_csv,
+                "expect_fixture.csv": expect_fixture_csv,
+            },
+        }
+
+    def test_quoted_reserved_word_column_names(self, project):
+        results = run_dbt(["run"])
+        assert len(results) == 2
+
+        results = run_dbt(["test"])