add DJANGO_CONFIGURATION_HOOK as optional parameter to allow customly configured settings instances

Author: JulianFeinauer

pytest_django/plugin.py

@@ -55,6 +55,7 @@
 
 SETTINGS_MODULE_ENV = "DJANGO_SETTINGS_MODULE"
 CONFIGURATION_ENV = "DJANGO_CONFIGURATION"
+CONFIGURATION_HOOK_ENV = "DJANGO_CONFIGURATION_HOOK"
 INVALID_TEMPLATE_VARS_ENV = "FAIL_INVALID_TEMPLATE_VARS"
 
 _report_header = []
@@ -98,6 +99,14 @@ def pytest_addoption(parser) -> None:
         default=None,
         help="Set DJANGO_CONFIGURATION.",
     )
+    group.addoption(
+        "--dch",
+        action="store",
+        type=str,
+        dest="dch",
+        default=None,
+        help="Set DJANGO_CONFIGURATION_HOOK.",
+    )
     group.addoption(
         "--nomigrations",
         "--no-migrations",
@@ -124,6 +133,9 @@ def pytest_addoption(parser) -> None:
     parser.addini(
         SETTINGS_MODULE_ENV, "Django settings module to use by pytest-django."
     )
+    parser.addini(
+        CONFIGURATION_HOOK_ENV, "Callback Hook to prepare Django settings alternatively."
+    )
 
     parser.addini(
         "django_find_project",
@@ -329,6 +341,7 @@ def _get_option_with_source(
 
     ds, ds_source = _get_option_with_source(options.ds, SETTINGS_MODULE_ENV)
     dc, dc_source = _get_option_with_source(options.dc, CONFIGURATION_ENV)
+    dch, dch_source = _get_option_with_source(options.dch, CONFIGURATION_HOOK_ENV)
 
     if ds:
         _report_header.append("settings: {} (from {})".format(ds, ds_source))
@@ -349,6 +362,34 @@ def _get_option_with_source(
 
         with _handle_import_error(_django_project_scan_outcome):
             dj_settings.DATABASES
+    elif dch:
+        # Forcefully load Django settings, throws ImportError or
+        # ImproperlyConfigured if settings cannot be loaded.
+        from django.conf import settings as dj_settings
+
+        # Call a HOOK that could initialize djangos
+        # object with a custom configuration
+
+        if "." not in dch:
+            raise ImportError(f"Invalid path for configuration hook: {dch}")
+
+        pkg_parts = dch.split(".")
+        module_path = ".".join(pkg_parts[:-1])
+        function_name = pkg_parts[-1]
+
+        import importlib
+
+        try:
+            mod = importlib.import_module(module_path)
+        except (ImportError, AttributeError):
+            raise ImportError(f"Unable to import module {module_path}")
+        func = getattr(mod, function_name, None)
+
+        if not func:
+            raise ImportError(f"No function found with name {function_name} in module {module_path}!")
+
+        # Call the function
+        func()
 
     _setup_django()
 

tests/test_django_settings_module.py

@@ -505,3 +505,32 @@ def test_no_django_settings_but_django_imported(testdir, monkeypatch) -> None:
     testdir.makeconftest("import django")
     r = testdir.runpytest_subprocess("--help")
     assert r.ret == 0
+
+
+def test_dch_ini(testdir, monkeypatch) -> None:
+    monkeypatch.delenv("DJANGO_SETTINGS_MODULE")
+    testdir.makeini(
+        """
+       [pytest]
+       DJANGO_CONFIGURATION_HOOK = tpkg.test.setup
+    """
+    )
+    pkg = testdir.mkpydir("tpkg")
+    pkg.join("test.py").write(
+        """
+# Test
+from django.conf import settings
+
+def setup():
+  settings.configure() 
+""")
+    testdir.makepyfile(
+        """
+        import os
+
+        def test_ds():
+            pass
+    """
+    )
+    result = testdir.runpytest_subprocess()
+    assert result.ret == 0