[carpentries#2062] Conditionally enable views based on feature flag

This will become useful for Instructor Recruitment views.

amy/workshops/base_views.py

@@ -1,4 +1,5 @@
 from smtplib import SMTPException
+from typing import Optional
 
 from django.conf import settings
 from django.contrib import messages
@@ -430,3 +431,18 @@ def get(self, request, *args, **kwargs):
         requested_person_id = self.kwargs.get(self.person_url_kwarg)
         assign(request, self.object, requested_person_id)
         return super().get(request, *args, **kwargs)
+
+
+class ConditionallyEnabledMixin:
+    """Mixin for enabling views based on feature flag."""
+
+    view_enabled: Optional[bool] = None
+
+    def get_view_enabled(self) -> bool:
+        return self.view_enabled is True
+
+    def dispatch(self, request, *args, **kwargs):
+        if self.get_view_enabled() is not True:
+            raise Http404("Page not found")
+
+        return super().dispatch(request, *args, **kwargs)

amy/workshops/tests/test_base_views.py

@@ -0,0 +1,73 @@
+from unittest.mock import patch
+
+from django.http.response import Http404
+from django.test import TestCase
+
+from workshops.base_views import ConditionallyEnabledMixin
+
+
+class FakeView:
+    """Used in the tests below."""
+
+    def dispatch(self, request, *args, **kwargs):
+        pass
+
+
+class TestConditionallyEnabledView(TestCase):
+    def test_disabled_view_through_parameter(self):
+        # Arrange
+        class View(ConditionallyEnabledMixin, FakeView):
+            pass
+
+        view = View()
+        view.view_enabled = False
+
+        # Act & Assert
+        with patch.object(FakeView, "dispatch") as mock_dispatch:
+            with self.assertRaises(Http404):
+                view.dispatch(None)
+            mock_dispatch.assert_not_called()
+
+    def test_disabled_view_through_method(self):
+        # Arrange
+        class View(ConditionallyEnabledMixin, FakeView):
+            def get_view_enabled(self) -> bool:
+                return False
+
+        view = View()
+
+        # Act & Assert
+        with patch.object(FakeView, "dispatch") as mock_dispatch:
+            with self.assertRaises(Http404):
+                view.dispatch(None)
+            mock_dispatch.assert_not_called()
+
+    def test_enabled_view_through_parameter(self):
+        # Arrange
+        class View(ConditionallyEnabledMixin, FakeView):
+            pass
+
+        view = View()
+        view.view_enabled = True
+
+        with patch.object(FakeView, "dispatch") as mock_dispatch:
+            # Act
+            view.dispatch(None)
+
+            # Assert
+            mock_dispatch.assert_called_once()
+
+    def test_enabled_view_through_method(self):
+        # Arrange
+        class View(ConditionallyEnabledMixin, FakeView):
+            def get_view_enabled(self) -> bool:
+                return True
+
+        view = View()
+
+        with patch.object(FakeView, "dispatch") as mock_dispatch:
+            # Act
+            view.dispatch(None)
+
+            # Assert
+            mock_dispatch.assert_called_once()