added to apps.dashboard.views, share_list() FBV, a try/except catch that accounts for nonexistent users; .test.test_views ensures functionality

src/apps/dashboard/tests/test_views.py

@@ -201,3 +201,11 @@ class ShareListTest(TestCase):
             data={"recipient": "alice@example.com"},
         )
         self.assertIn(alice, our_list.shared_with.all())
+
+    def test_post_with_nonexistent_email_redirects_to_list(self):
+        our_list = List.objects.create()
+        response = self.client.post(
+            f"/apps/dashboard/{our_list.id}/share_list",
+            data={"recipient": "nobody@example.com"},
+        )
+        self.assertRedirects(response, f"/apps/dashboard/{our_list.id}/")

src/apps/dashboard/views.py

@@ -40,6 +40,9 @@ def my_lists(request, user_id):
 
 def share_list(request, list_id):
     our_list = List.objects.get(id=list_id)
+    try:
         recipient = User.objects.get(email=request.POST["recipient"])
         our_list.shared_with.add(recipient)
+    except User.DoesNotExist:
+        pass
     return redirect(our_list)