make settings file loading testable

ca/ca/settings.py

@@ -26,7 +26,6 @@
 
 # Build paths inside the project like this: os.path.join(BASE_DIR, ...)
 BASE_DIR = Path(__file__).resolve().parent.parent  # ca/
-SETTINGS_YAML = BASE_DIR / "ca" / "settings.yaml"
 
 DEBUG = False
 
@@ -209,30 +208,36 @@
 
 
 # CONFIGURATION_DIRECTORY is set by the SystemD ConfigurationDirectory= directive.
-_settings_files: List[Tuple[str, "os.PathLike[str]"]] = []
 SETTINGS_DIRS = os.environ.get("DJANGO_CA_SETTINGS", os.environ.get("CONFIGURATION_DIRECTORY", ""))
 
-for _path in [BASE_DIR / p for p in SETTINGS_DIRS.split(":")]:
-    if not _path.exists():
-        raise ImproperlyConfigured(f"{_path}: No such file or directory.")
-
-    if _path.is_dir():
-        # exclude files that don't end with '.yaml' and any directories
-        _settings_files += [
-            (_f, _path)
-            for _f in os.listdir(_path)
-            if _f.endswith(".yaml") and not os.path.isdir(os.path.join(_path, _f))
-        ]
-    else:
-        _settings_files.append((_path.name, _path.parent))
 
-_settings_files = sorted(_settings_files)
-if SETTINGS_YAML.exists():
-    _settings_files.append((SETTINGS_YAML.name, SETTINGS_YAML.parent))
+def _get_settings_files(base_dir: Path, dirs: str) -> List[Tuple[str, Path]]:
+    settings_files: List[Tuple[str, Path]] = []
+
+    for path in [base_dir / p for p in dirs.split(":")]:
+        if not path.exists():
+            raise ImproperlyConfigured(f"{path}: No such file or directory.")
+
+        if path.is_dir():
+            # exclude files that don't end with '.yaml' and any directories
+            settings_files += sorted(
+                [(_f.name, path) for _f in path.iterdir() if _f.suffix == ".yaml" and not _f.is_dir()]
+            )
+        else:
+            settings_files.append((path.name, path.parent))
+
+    settings_yaml = base_dir / "ca" / "settings.yaml"
+    if settings_yaml.exists():
+        settings_files.append((settings_yaml.name, settings_yaml.parent))
+
+    return settings_files
+
 
 if not _skip_local_config and yaml is not False:  # type: ignore[comparison-overlap]
+    _settings_files = _get_settings_files(BASE_DIR, SETTINGS_DIRS)
+
     for _filename, _filename_path in _settings_files:
-        _full_path = os.path.join(_path, _filename)
+        _full_path = _filename_path / _filename
         with open(_full_path, encoding="utf-8") as stream:
             data = yaml.safe_load(stream)
         if data is None:

ca/django_ca/tests/conftest.py

@@ -77,7 +77,8 @@ def pytest_configure(config: "PytestConfig") -> None:
     # Add a header to log important software versions
     print("Testing with:")
     print("* Python: ", sys.version.replace("\n", ""))
-    installed_versions = {p.name: p.version for p in importlib.metadata.distributions()}
+    # pragma: only py<3.10  # p.name is available as a shortcut to p.metadata["Name"] in Python 3.10
+    installed_versions = {p.metadata["Name"]: p.version for p in importlib.metadata.distributions()}
     for pkg in sorted(["Django", "acme", "cryptography", "celery", "idna", "josepy"]):
         print(f"* {pkg}: {installed_versions[pkg]}")
     print(f"* Selenium tests: {not skip_selenium}")

ca/django_ca/tests/fixtures/settings/base/ca/settings.yaml

@@ -0,0 +1 @@
+SETTINGS_YAML: True

ca/django_ca/tests/fixtures/settings/dirs/settings_dir/01-settings.yaml

@@ -0,0 +1 @@
+SETTINGS_DIR_ONE: True

ca/django_ca/tests/fixtures/settings/dirs/settings_dir/02-settings.yaml

@@ -0,0 +1 @@
+SETTINGS_DIR_TWO: True

ca/django_ca/tests/fixtures/settings/dirs/single-file.yaml

@@ -0,0 +1 @@
+SINGLE_FILE: True

ca/django_ca/tests/test_settings.py

@@ -11,20 +11,61 @@
 # You should have received a copy of the GNU General Public License along with django-ca. If not, see
 # <http://www.gnu.org/licenses/>.
 
+# pylint: disable=redefined-outer-name  # does not work with fixtures
+
 """Test cases for the ``ca_settings`` module."""
 
+import typing
 from datetime import timedelta
+from importlib import import_module
+from pathlib import Path
+from typing import List, Tuple
 from unittest import mock
 
 from cryptography import x509
 from cryptography.hazmat.primitives import hashes
 from cryptography.x509.oid import NameOID
 
+from django.conf import settings
 from django.test import TestCase
 
+import pytest
+
 from django_ca import ca_settings
 from django_ca.tests.base.mixins import TestCaseMixin
 
+GET_SETTINGS_FILES = typing.Callable[[Path, str], List[Tuple[str, Path]]]  # pylint: disable=invalid-name
+
+
+@pytest.fixture(scope="module")
+def get_settings_files() -> GET_SETTINGS_FILES:
+    """Fixture to import to the _get_settings_files() function."""
+    mod = import_module("ca.settings")
+    return typing.cast(GET_SETTINGS_FILES, getattr(mod, "_get_settings_files"))
+
+
+def test_no_settings_files(tmp_path: Path, get_settings_files: GET_SETTINGS_FILES) -> None:
+    """Test no settings.yaml exists and no DJANGO_CA_SETTINGS env variable set."""
+    assert get_settings_files(tmp_path, "") == []
+
+
+def test_with_settings_files(get_settings_files: GET_SETTINGS_FILES) -> None:
+    """Test a full list of settings files."""
+    base_dir = settings.FIXTURES_DIR / "settings" / "base"
+    single_file = settings.FIXTURES_DIR / "settings" / "dirs" / "single-file.yaml"
+    settings_dir = settings.FIXTURES_DIR / "settings" / "dirs" / "settings_dir"
+    settings_files = get_settings_files(base_dir, f"{single_file}:{settings_dir}")
+    assert settings_files == [
+        ("single-file.yaml", single_file.parent),
+        ("01-settings.yaml", settings_dir),
+        ("02-settings.yaml", settings_dir),
+        ("settings.yaml", base_dir / "ca"),
+    ]
+
+    # Assert that all files actually exist
+    for name, path in settings_files:
+        assert (path / name).exists() is True
+
 
 class SettingsTestCase(TestCase):
     """Test some standard settings."""

pyproject.toml

@@ -365,7 +365,7 @@ min-similarity-lines = 16
 [tool.pytest.ini_options]
 DJANGO_SETTINGS_MODULE = "ca.test_settings"
 addopts = [
-    "--cov=ca/django_ca/",
+    "--cov",
     "--cov-report=html:docs/build/coverage/",
     "--cov-fail-under=100",
     "--random-order",