feat!: Remove django-admin default login (#29876)

* feat!: Remove django-admin default login

cms/djangoapps/contentstore/tests/test_admin.py

@@ -0,0 +1,32 @@
+"""
+Tests that verify that the admin view loads.
+
+This is not inside a django app because it is a global property of the system.
+"""
+import ddt
+from django.test import TestCase
+from django.urls import reverse
+from edx_toggles.toggles.testutils import override_waffle_flag
+
+from openedx.core.djangoapps.user_authn.config.waffle import ADMIN_AUTH_REDIRECT_TO_LMS
+
+
+@ddt.ddt
+class TestAdminView(TestCase):
+    """
+    Tests of the admin view.
+    """
+    @override_waffle_flag(ADMIN_AUTH_REDIRECT_TO_LMS, True)
+    @ddt.data('/admin/', '/admin/login', reverse('admin:login'))
+    def test_admin_login_redirect(self, admin_url):
+        """Admin login will redirect towards the site login page."""
+        response = self.client.get(admin_url, follow=True)
+        assert any('/login/edx-oauth2/?next=' in r[0] for r in response.redirect_chain)
+
+    def test_admin_login_default(self):
+        """Without flag Admin login will redirect towards the admin default login page."""
+        response = self.client.get('/admin/', follow=True)
+        assert response.status_code == 200
+        self.assertIn('/admin/login/?next=/admin/', response.redirect_chain[0])
+        assert len(response.redirect_chain) == 1
+        assert response.template_name == ['admin/login.html']