breaking(pytest_plugins/operator_groups): Raise exception if test mis…

…sing group number (#113)

Fixes #106

If a test is missing a group number, it is almost certainly a mistake
instead of intentional. Previously, if the test was missing a group
number, it was marked as skipped (which will cause the job to pass on
GitHub CI).

python/pytest_plugins/pytest_operator_groups/pytest_operator_groups/plugin.py

@@ -60,7 +60,9 @@ class Group:
     groups: set[Group] = set()
     for function in items:
         if (group_number := _get_group_number(function)) is None:
-            continue
+            raise Exception(
+                f"{function} missing group number. Docs: https://github.com/canonical/data-platform-workflows/blob/main/.github/workflows/integration_test_charm.md#step-3-split-test-functions-into-groups"
+            )
         # Example: "integration.relations.test_database"
         name = function.module.__name__
         assert name.split(".")[0] == "integration"
@@ -101,8 +103,9 @@ def pytest_collection_modifyitems(config, items):
         for function in items:
             group_number = _get_group_number(function)
             if group_number is None:
-                function.add_marker(pytest.mark.skip("Missing group number"))
-                filtered_items.append(function)
+                raise Exception(
+                    f"{function} missing group number. Docs: https://github.com/canonical/data-platform-workflows/blob/main/.github/workflows/integration_test_charm.md#step-3-split-test-functions-into-groups"
+                )
             elif group_number == config.option.group:
                 filtered_items.append(function)
         items[:] = filtered_items