Implement the --django-debug plugin option with tests

docs/changelog.rst

@@ -1,5 +1,12 @@
 Changelog
-=========
+
+Unreleased
+----------
+
+Features
+^^^^^^^^
+
+* Add a new option `--django-debug-mode` to specify the default DEBUG setting (#228)
 
 3.4.8 (2019-02-26)
 ------------------

docs/configuring_django.rst

@@ -104,3 +104,16 @@ itself::
         project.app.signals.something = noop
 
 This plugin can then be used e.g. via ``-p`` in :pytest-confval:`addopts`.
+
+``DEBUG`` setting during the test run
+-------------------------------------
+
+Django's test runner forces ``DEBUG`` to be ``False`` by default, and so
+does ``pytest-django``.
+This can be controlled using the ``--django-debug-mode`` command line option::
+
+    $ pytest --django-debug-mode True|False|None
+
+``None`` do not override the default
+``True`` override ``DEBUG`` to be ``True``
+``False`` override ``DEBUG`` to be ``False``

pytest_django/plugin.py

@@ -5,6 +5,7 @@
 """
 
 import contextlib
+from distutils.util import strtobool
 import inspect
 from functools import reduce
 import os
@@ -106,6 +107,13 @@ def pytest_addoption(parser):
         default=False,
         help="Enable Django migrations on test setup",
     )
+    group._addoption(
+        "--django-debug-mode",
+        action="store",
+        dest="django_debug_mode",
+        default="None",
+        help="Configure Django's DEBUG setting."
+    )
     parser.addini(
         CONFIGURATION_ENV, "django-configurations class to use by pytest-django."
     )
@@ -463,11 +471,21 @@ def django_test_environment(request):
     """
     if django_settings_is_configured():
         _setup_django()
-        from django.conf import settings as dj_settings
         from django.test.utils import setup_test_environment, teardown_test_environment
 
-        dj_settings.DEBUG = False
-        setup_test_environment()
+        setup_test_environment_kwargs = {}
+
+        django_debug_mode = request.config.getvalue("django_debug_mode")
+        if django_debug_mode != "None":
+            import django
+            debug = bool(strtobool(django_debug_mode))
+            if django.VERSION >= (1, 11):
+                setup_test_environment_kwargs["debug"] = debug
+            else:
+                from django.conf import settings as dj_settings
+                dj_settings.DEBUG = debug
+
+        setup_test_environment(**setup_test_environment_kwargs)
         request.addfinalizer(teardown_test_environment)
 
 

tests/test_django_settings_module.py

@@ -279,10 +279,9 @@ def test_settings():
     assert result.ret == 0
 
 
-def test_debug_false(testdir, monkeypatch):
-    monkeypatch.delenv("DJANGO_SETTINGS_MODULE")
-    testdir.makeconftest(
-        """
+def test_no_debug_override(testdir, monkeypatch):
+    monkeypatch.delenv('DJANGO_SETTINGS_MODULE')
+    testdir.makeconftest("""
         from django.conf import settings
 
         def pytest_configure():
@@ -293,18 +292,65 @@ def pytest_configure():
                                    'NAME': ':memory:'}},
                                INSTALLED_APPS=['django.contrib.auth',
                                                'django.contrib.contenttypes',])
-    """
-    )
+    """)
 
-    testdir.makepyfile(
-        """
+    testdir.makepyfile("""
+        from django.conf import settings
+        def test_debug_is_unchanged():
+            assert settings.DEBUG is True
+    """)
+
+    r = testdir.runpytest_subprocess('--django-debug-mode=None')
+    assert r.ret == 0
+
+
+def test_override_debug_to_false(testdir, monkeypatch):
+    monkeypatch.delenv('DJANGO_SETTINGS_MODULE')
+    testdir.makeconftest("""
+        from django.conf import settings
+
+        def pytest_configure():
+            settings.configure(SECRET_KEY='set from pytest_configure',
+                               DEBUG=True,
+                               DATABASES={'default': {
+                                   'ENGINE': 'django.db.backends.sqlite3',
+                                   'NAME': ':memory:'}},
+                               INSTALLED_APPS=['django.contrib.auth',
+                                               'django.contrib.contenttypes',])
+    """)
+
+    testdir.makepyfile("""
         from django.conf import settings
         def test_debug_is_false():
             assert settings.DEBUG is False
-    """
-    )
+    """)
 
-    r = testdir.runpytest_subprocess()
+    r = testdir.runpytest_subprocess('--django-debug-mode=False')
+    assert r.ret == 0
+
+
+def test_override_debug_to_true(testdir, monkeypatch):
+    monkeypatch.delenv('DJANGO_SETTINGS_MODULE')
+    testdir.makeconftest("""
+        from django.conf import settings
+
+        def pytest_configure():
+            settings.configure(SECRET_KEY='set from pytest_configure',
+                               DEBUG=False,
+                               DATABASES={'default': {
+                                   'ENGINE': 'django.db.backends.sqlite3',
+                                   'NAME': ':memory:'}},
+                               INSTALLED_APPS=['django.contrib.auth',
+                                               'django.contrib.contenttypes',])
+    """)
+
+    testdir.makepyfile("""
+        from django.conf import settings
+        def test_debug_is_true():
+            assert settings.DEBUG is True
+    """)
+
+    r = testdir.runpytest_subprocess('--django-debug-mode=True')
     assert r.ret == 0