Django 3 compat (#7058)

* First pass at Django 3.0 compat

* Drop Guardian for 1.11 tests, since we're installing an incompatible version

* Fix ROOT_URLCONF override in test case

* Fix typo

Co-Authored-By: Rémy HUBSCHER <hubscher.remy@gmail.com>

* Linting

.travis.yml

@@ -14,13 +14,16 @@ matrix:
       - { python: "3.6", env: DJANGO=2.0 }
       - { python: "3.6", env: DJANGO=2.1 }
       - { python: "3.6", env: DJANGO=2.2 }
+      - { python: "3.6", env: DJANGO=3.0 }
       - { python: "3.6", env: DJANGO=master }
 
       - { python: "3.7", env: DJANGO=2.0 }
       - { python: "3.7", env: DJANGO=2.1 }
       - { python: "3.7", env: DJANGO=2.2 }
+      - { python: "3.7", env: DJANGO=3.0 }
       - { python: "3.7", env: DJANGO=master }
 
+      - { python: "3.8", env: DJANGO=3.0 }
       - { python: "3.8", env: DJANGO=master }
 
       - { python: "3.8", env: TOXENV=base }

requirements/requirements-optionals.txt

@@ -2,7 +2,7 @@
 psycopg2-binary>=2.8.2, <2.9
 markdown==3.1.1
 pygments==2.4.2
-django-guardian==1.5.0
+django-guardian==2.1.0
 django-filter>=2.2.0, <2.3
 coreapi==2.3.1
 coreschema==0.0.4

tests/conftest.py

@@ -67,19 +67,22 @@ def pytest_configure(config):
     )
 
     # guardian is optional
-    try:
-        import guardian  # NOQA
-    except ImportError:
-        pass
-    else:
-        settings.ANONYMOUS_USER_ID = -1
-        settings.AUTHENTICATION_BACKENDS = (
-            'django.contrib.auth.backends.ModelBackend',
-            'guardian.backends.ObjectPermissionBackend',
-        )
-        settings.INSTALLED_APPS += (
-            'guardian',
-        )
+    # Note that for the test cases we're installing a version of django-guardian
+    # that's only compatible with Django 2.0+.
+    if django.VERSION >= (2, 0, 0):
+        try:
+            import guardian  # NOQA
+        except ImportError:
+            pass
+        else:
+            settings.ANONYMOUS_USER_ID = -1
+            settings.AUTHENTICATION_BACKENDS = (
+                'django.contrib.auth.backends.ModelBackend',
+                'guardian.backends.ObjectPermissionBackend',
+            )
+            settings.INSTALLED_APPS += (
+                'guardian',
+            )
 
     if config.getoption('--no-pkgroot'):
         sys.path.pop(0)

tests/test_relations.py

@@ -145,9 +145,12 @@ class TestProxiedPrimaryKeyRelatedField(APISimpleTestCase):
         assert representation == self.instance.pk.int
 
 
-@override_settings(ROOT_URLCONF=[
+urlpatterns = [
     url(r'^example/(?P<name>.+)/$', lambda: None, name='example'),
-])
+]
+
+
+@override_settings(ROOT_URLCONF='tests.test_relations')
 class TestHyperlinkedRelatedField(APISimpleTestCase):
     def setUp(self):
         self.queryset = MockQueryset([

tox.ini

@@ -4,6 +4,7 @@ envlist =
        {py35,py36,py37}-django20,
        {py35,py36,py37}-django21
        {py35,py36,py37}-django22
+       {py36,py37,py38}-django30,
        {py36,py37,py38}-djangomaster,
        base,dist,lint,docs,
 
@@ -13,6 +14,7 @@ DJANGO =
     2.0: django20
     2.1: django21
     2.2: django22
+    3.0: django30
     master: djangomaster
 
 [testenv]
@@ -26,6 +28,7 @@ deps =
         django20: Django>=2.0,<2.1
         django21: Django>=2.1,<2.2
         django22: Django>=2.2,<3.0
+        django30: Django==3.0rc1
         djangomaster: https://github.com/django/django/archive/master.tar.gz
         -rrequirements/requirements-testing.txt
         -rrequirements/requirements-optionals.txt