tests: run wcs tests only against python 3 (#40008)

tests/conftest.py

@@ -5,10 +5,14 @@ import django_webtest
 
 from django.core.files import File
 from django.core.cache import cache
+from django.utils import six
 from io import BytesIO
 
 from utils import make_resource
 
+if six.PY2:
+    collect_ignore = ['wcs/']
+
 
 @pytest.fixture(autouse=True)
 def media(settings, tmpdir):