Pass admin URL to API for registration email

This follows the pattern for invite emails where the admin app tells the
API which domain to use when generating the link.

app/notify_client/user_api_client.py

@@ -101,7 +101,10 @@ class UserApiClient(NotifyAdminAPIClient):
         self.post(endpoint, data=data)
 
     def send_verify_email(self, user_id, to):
-        data = {'to': to}
+        data = {
+            'to': to,
+            'admin_base_url': self.admin_url,
+        }
         endpoint = '/user/{0}/email-verification'.format(user_id)
         self.post(endpoint, data=data)
 

tests/app/notify_client/test_user_client.py

@@ -325,3 +325,22 @@ def test_reset_password(
             'admin_base_url': 'http://localhost:6012',
         },
     )
+
+
+def test_send_registration_email(
+    mocker,
+    fake_uuid,
+):
+    mock_post = mocker.patch(
+        'app.notify_client.user_api_client.UserApiClient.post'
+    )
+
+    user_api_client.send_verify_email(fake_uuid, 'test@example.com')
+
+    mock_post.assert_called_once_with(
+        f'/user/{fake_uuid}/email-verification',
+        data={
+            'to': 'test@example.com',
+            'admin_base_url': 'http://localhost:6012',
+        },
+    )