Implement the --django-debug plugin option with tests

Author: dulacp

docs/changelog.rst

@@ -1,6 +1,14 @@
 Changelog
 =========
 
+Unreleased
+----------
+
+Features
+^^^^^^^^
+
+* Added a new option `--django-debug` to specify the default DEBUG setting (#228)
+
 3.1.2
 -----
 

docs/configuring_django.rst

@@ -83,3 +83,17 @@ This can be done from your project's ``conftest.py`` file::
     def pytest_configure():
         settings.configure(DATABASES=...)
 
+
+``DEBUG`` setting during the test run
+-------------------------------------
+
+By default, django test runner behavior is to force DEBUG setting to False. So does the ``pytest-django``.
+But sometimes, especially for functional tests, you might want to avoid this, to debug why certain page does not work.
+
+Command Line Option::
+
+    $ py.test --django-debug True|False|None
+
+``None`` ensure there is no override of the test settings DEBUG value
+``True`` override DEBUG to True
+``False`` override DEBUG to False

pytest_django/plugin.py

@@ -5,6 +5,7 @@
 """
 
 import contextlib
+from distutils.util import strtobool
 import inspect
 from functools import reduce
 import os
@@ -66,6 +67,9 @@ def pytest_addoption(parser):
     group._addoption('--migrations',
                      action='store_false', dest='nomigrations', default=False,
                      help='Enable Django migrations on test setup')
+    group._addoption('--django-debug',
+                     action='store', dest='djangodebug', default='False',
+                     help='Configure the DEBUG setting. Defaults to False')
     parser.addini(CONFIGURATION_ENV,
                   'django-configurations class to use by pytest-django.')
     group._addoption('--liveserver', default=None,
@@ -335,7 +339,8 @@ def django_test_environment(request):
         from django.conf import settings as dj_settings
         from django.test.utils import (setup_test_environment,
                                        teardown_test_environment)
-        dj_settings.DEBUG = False
+        if request.config.getvalue('djangodebug') != 'None':
+            dj_settings.DEBUG = bool(strtobool(request.config.getvalue('djangodebug')))
         setup_test_environment()
         request.addfinalizer(teardown_test_environment)
 

tests/test_django_settings_module.py

@@ -275,6 +275,81 @@ def test_debug_is_false():
     assert r.ret == 0
 
 
+def test_no_debug_override(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_unchanged():
+            assert settings.DEBUG is True
+    """)
+
+    r = testdir.runpytest_subprocess('--django-debug=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('--django-debug=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=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_true():
+            assert settings.DEBUG is True
+    """)
+
+    r = testdir.runpytest_subprocess('--django-debug=True')
+    assert r.ret == 0
+
+
 @pytest.mark.skipif(not hasattr(django, 'setup'),
                     reason="This Django version does not support app loading")
 @pytest.mark.django_project(extra_settings="""