Add test case for #10017

tests/functional/unit_testing/fixtures.py

@@ -1041,3 +1041,22 @@ def external_package():
             "external_model.sql": external_package__external_model_sql,
         },
     }
+
+
+model_select_1_sql = """
+select 1 as id
+"""
+
+model_select_2_sql = """
+select 2 as id
+"""
+
+test_expect_2_yml = """
+unit_tests:
+  - name: test_my_model
+    model: my_model
+    given: []
+    expect:
+      rows:
+        - {id: 2}
+"""

tests/functional/unit_testing/test_state.py

@@ -15,6 +15,9 @@
     test_my_model_simple_fixture_yml,
     test_my_model_fixture_csv,
     test_my_model_b_fixture_csv as test_my_model_fixture_csv_modified,
+    model_select_1_sql,
+    model_select_2_sql,
+    test_expect_2_yml,
 )
 
 
@@ -131,3 +134,23 @@ def test_unit_test_defer_state(self, project):
         results = run_dbt(["test", "--defer", "--state", "state"], expect_pass=False)
         assert len(results) == 4
         assert sorted([r.status for r in results]) == ["fail", "pass", "pass", "pass"]
+
+
+
+class TestUnitTestDeferDoesntOverwrite(UnitTestState):
+    @pytest.fixture(scope="class")
+    def models(self):
+        return {"my_model.sql": model_select_1_sql, "test_my_model.yml": test_expect_2_yml}
+
+    def test_unit_test_defer_state(self, project):
+        run_dbt(["test"], expect_pass=False)
+        self.copy_state(project.project_root)
+        write_file(
+            model_select_2_sql,
+            project.project_root,
+            "models",
+            "my_model.sql",
+        )
+        results = run_dbt(["test", "--defer", "--state", "state"])
+        assert len(results) == 1
+        assert sorted([r.status for r in results]) == ["pass"]