Add test of metadata-based freshness mechanism

dev-requirements.txt

@@ -1,6 +1,6 @@
 # install latest changes in dbt-core
 # TODO: how to automate switching from develop to version branches?
-git+https://github.com/dbt-labs/dbt-core.git#egg=dbt-core&subdirectory=core
+git+https://github.com/dbt-labs/dbt-core.git@paw%2Fmetadata-freshness#egg=dbt-core&subdirectory=core
 git+https://github.com/dbt-labs/dbt-core.git#egg=dbt-tests-adapter&subdirectory=tests/adapter
 
 # if version 1.x or greater -> pin to major version

tests/functional/adapter/test_get_last_relation_modified.py

@@ -0,0 +1,33 @@
+import os
+import pytest
+
+from dbt.tests.util import run_dbt
+
+freshness_via_metadata_schema_yml = """version: 2
+sources:
+  - name: test_source
+    freshness:
+      warn_after: {count: 10, period: hour}
+      error_after: {count: 1, period: day}
+    schema: "{{ env_var('DBT_TEST_SCHEMA_NAME_VARIABLE') }}"
+    tables:
+      - name: test_table
+"""
+
+
+class TestGetLastRelationModified:
+    @pytest.fixture(scope="class", autouse=True)
+    def set_env_vars(self, project):
+        os.environ["DBT_TEST_SCHEMA_NAME_VARIABLE"] = project.test_schema
+        yield
+        del os.environ["DBT_TEST_SCHEMA_NAME_VARIABLE"]
+
+    @pytest.fixture(scope="class")
+    def models(self):
+        return {"schema.yml": freshness_via_metadata_schema_yml}
+
+    def test_get_last_relation_modified(self, project, set_env_vars):
+        project.run_sql(
+            f"create table {project.test_schema}.test_table (id integer autoincrement, name varchar(100) not null);"
+        )
+        run_dbt(["source", "freshness"])