Add test for the nox.default module

Also creates a `tests.utils` module to store common test utilities. For
now it only provides a common error message for when the repository
types handled don't match the expectation.

Some `__init__.py` files are added to `tests/` to be able to use relative
imports.

Signed-off-by: Leandro Lucarella <leandro.lucarella@frequenz.com>

Author: llucax

tests/__init__.py

@@ -0,0 +1,4 @@
+# License: MIT
+# Copyright © 2023 Frequenz Energy-as-a-Service GmbH
+
+"""Tests for the repository."""

tests/nox/__init__.py

@@ -0,0 +1,4 @@
+# License: MIT
+# Copyright © 2023 Frequenz Energy-as-a-Service GmbH
+
+"""Tests for the nox package."""

tests/nox/test_default.py

@@ -0,0 +1,27 @@
+# License: MIT
+# Copyright © 2023 Frequenz Energy-as-a-Service GmbH
+
+"""Tests for the nox.default module."""
+
+from frequenz.repo import config
+from frequenz.repo.config.nox import default
+
+from .. import utils
+
+
+def test_all_repository_types_are_handled() -> None:
+    """Test that all repository types handled match the defined in RepositoryType."""
+    expected = {
+        *{f"{repo_type.value}_config" for repo_type in config.RepositoryType},
+        *{f"{repo_type.value}_command_options" for repo_type in config.RepositoryType},
+        "common_config",
+        "common_command_options",
+    }
+
+    defined = {
+        f
+        for f in dir(default)
+        if not f.startswith("_")
+        and (f.endswith("_config") or f.endswith("_command_options"))
+    }
+    assert defined == expected, utils.MSG_UNEXPECTED_REPO_TYPES

tests/utils.py

@@ -0,0 +1,12 @@
+# License: MIT
+# Copyright © 2023 Frequenz Energy-as-a-Service GmbH
+
+"""Test utilities."""
+
+MSG_UNEXPECTED_REPO_TYPES = """\
+Missing (or unexpected) repository types. Please make sure update:
+
+- the documentation (in particular in src/frequenz/repo/config/__init__.py)
+- the code (including all packages)
+- the tests
+"""