Add functional tests for custom incremental strategies names 'microbatch'

tests/functional/microbatch/test_microbatch.py

@@ -7,6 +7,7 @@
     patch_microbatch_end_time,
     relation_from_name,
     run_dbt,
+    run_dbt_and_capture,
     write_file,
 )
 
@@ -69,6 +70,81 @@
 select * from {{ source('seed_sources', 'raw_source') }}
 """
 
+custom_microbatch_strategy = """
+{% macro get_incremental_microbatch_sql(arg_dict) %}
+    {% do log('custom microbatch strategy', info=True) %}
+
+     {%- set dest_cols_csv = get_quoted_csv(arg_dict["dest_columns"] | map(attribute="name")) -%}
+
+    insert into {{ arg_dict["target_relation"] }} ({{ dest_cols_csv }})
+    (
+        select {{ dest_cols_csv }}
+        from {{ arg_dict["temp_relation"] }}
+    )
+
+{% endmacro %}
+"""
+
+
+class BaseMicrobatchCustomUserStrategy:
+    @pytest.fixture(scope="class")
+    def models(self):
+        return {
+            "input_model.sql": input_model_sql,
+            "microbatch_model.sql": microbatch_model_sql,
+        }
+
+    @pytest.fixture(scope="class")
+    def macros(self):
+        return {"microbatch.sql": custom_microbatch_strategy}
+
+
+class TestMicrobatchCustomUserStrategyDefault(BaseMicrobatchCustomUserStrategy):
+    def test_use_custom_microbatch_strategy_by_default(self, project):
+        with mock.patch.object(
+            type(project.adapter), "valid_incremental_strategies", lambda _: []
+        ):
+            # Initial run
+            run_dbt(["run"])
+
+            # Incremental run uses custom strategy
+            _, logs = run_dbt_and_capture(["run"])
+            assert "custom microbatch strategy" in logs
+
+
+class TestMicrobatchCustomUserStrategyEnvVarTrueValid(BaseMicrobatchCustomUserStrategy):
+    @mock.patch.dict(os.environ, {"DBT_EXPERIMENTAL_MICROBATCH": "True"})
+    def test_use_custom_microbatch_strategy_env_var_true_invalid_incremental_strategy(
+        self, project
+    ):
+        with mock.patch.object(
+            type(project.adapter), "valid_incremental_strategies", lambda _: ["microbatch"]
+        ):
+            # Initial run
+            run_dbt(["run"])
+
+            # Incremental run uses custom strategy
+            _, logs = run_dbt_and_capture(["run"])
+            assert "custom microbatch strategy" in logs
+
+
+# TODO: Consider a behaviour flag here if DBT_EXPERIMENTAL_MICROBATCH is removed
+# Since this causes an exception prior to using an override
+class TestMicrobatchCustomUserStrategyEnvVarTrueInvalid(BaseMicrobatchCustomUserStrategy):
+    @mock.patch.dict(os.environ, {"DBT_EXPERIMENTAL_MICROBATCH": "True"})
+    def test_use_custom_microbatch_strategy_env_var_true_invalid_incremental_strategy(
+        self, project
+    ):
+        with mock.patch.object(
+            type(project.adapter), "valid_incremental_strategies", lambda _: []
+        ):
+            # Initial run
+            run_dbt(["run"])
+
+            # Incremental run fails
+            _, logs = run_dbt_and_capture(["run"], expect_pass=False)
+            assert "'microbatch' is not valid" in logs
+
 
 class TestMicrobatchCLI:
     @pytest.fixture(scope="class")