Add separate endpoint to update a single user attr

tests/app/user/test_rest.py

@@ -1,4 +1,5 @@
 import json
+import pytest
 
 from flask import url_for, current_app
 from freezegun import freeze_time
@@ -180,6 +181,29 @@ def test_put_user(notify_api, notify_db, notify_db_session, sample_service):
             assert sorted(expected_permissions) == sorted(fetched['permissions'][str(sample_service.id)])
 
 
+@pytest.mark.parametrize('user_attribute, user_value', [
+    ('name', 'New User'),
+    ('email_address', 'newuser@mail.com'),
+    ('mobile_number', '+4407700900460')
+])
+def test_put_user_attribute(client, sample_user, user_attribute, user_value):
+    assert getattr(sample_user, user_attribute) != user_value
+    update_dict = {
+        user_attribute: user_value
+    }
+    auth_header = create_authorization_header()
+    headers = [('Content-Type', 'application/json'), auth_header]
+
+    resp = client.put(
+        url_for('user.update_user_attribute', user_id=sample_user.id),
+        data=json.dumps(update_dict),
+        headers=headers)
+
+    assert resp.status_code == 200
+    json_resp = json.loads(resp.get_data(as_text=True))
+    assert json_resp['data'][user_attribute] == user_value
+
+
 def test_put_user_update_password(notify_api,
                                   notify_db,
                                   notify_db_session,