Refactor test_archive_not_allowed to functional test

We do already have tests that ensure "extra" keys aren't allowed in
the dbt_project.yaml. This test is different because it's checking that
a specific key, `archive`, isn't allowed. We do this because at one point
in time `archive` _was_ an allowed key. Specifically, we stopped allowing
`archive` in dbt-core 0.15.0 via commit [f26948d](f26948d).
Given that it's been 5 years and a major version, we could probably remove
this test, but let's keep it around unless we start supporting `archive` again.

tests/functional/basic/test_project.py

@@ -139,3 +139,31 @@ def test_version_specifier_checks_before_yaml_validation(self, project) -> None:
         assert result.exception is not None
         assert isinstance(result.exception, DbtProjectError)
         assert "This version of dbt is not supported"
+
+
+class TestArchiveNotAllowed:
+    """At one point in time we supported an 'archive' key in projects, but no longer"""
+
+    def test_archive_not_allowed(self, project):
+        runner = dbtRunner()
+
+        config_update = {
+            "archive": {
+                "source_schema": "a",
+                "target_schema": "b",
+                "tables": [
+                    {
+                        "source_table": "seed",
+                        "target_table": "archive_actual",
+                        "updated_at": "updated_at",
+                        "unique_key": """id || '-' || first_name""",
+                    },
+                ],
+            }
+        }
+        update_config_file(config_update, "dbt_project.yml")
+
+        result = runner.invoke(["parse"])
+        assert result.exception is not None
+        assert isinstance(result.exception, ProjectContractError)
+        assert "Additional properties are not allowed" in str(result.exception)

tests/unit/config/test_runtime.py

@@ -97,24 +97,6 @@ def from_parts(self, exc=None):
         else:
             return err
 
-    def test_archive_not_allowed(self):
-        self.default_project_data["archive"] = [
-            {
-                "source_schema": "a",
-                "target_schema": "b",
-                "tables": [
-                    {
-                        "source_table": "seed",
-                        "target_table": "archive_actual",
-                        "updated_at": "updated_at",
-                        "unique_key": """id || '-' || first_name""",
-                    },
-                ],
-            }
-        ]
-        with self.assertRaises(dbt.exceptions.ProjectContractError):
-            self.get_project()
-
     def test__warn_for_unused_resource_config_paths_empty(self):
         project = self.from_parts()
         dbt.flags.WARN_ERROR = True