ensure other 2FA pages also handle session id

specifically, the 2FA page when you first create an account is different to the login 2FA page
and also the 2FA page when you change your phone number is different as well

tests/app/main/views/test_verify.py

@@ -1,5 +1,7 @@
-from flask import url_for
+import uuid
+import json
 
+from flask import url_for
 from bs4 import BeautifulSoup
 
 
@@ -24,17 +26,28 @@ def test_should_return_verify_template(
 def test_should_redirect_to_add_service_when_sms_code_is_correct(
     client,
     api_user_active,
-    mock_get_user,
+    mocker,
     mock_update_user,
     mock_check_verify_code,
+    fake_uuid
 ):
+    api_user_active.current_session_id = str(uuid.UUID(int=1))
+    mocker.patch('app.user_api_client.get_user', return_value=api_user_active)
+
     with client.session_transaction() as session:
         session['user_details'] = {'email_address': api_user_active.email_address, 'id': api_user_active.id}
+        # user's only just created their account so no session in the cookie
+        session.pop('current_session_id', None)
+
     response = client.post(url_for('main.verify'),
                            data={'sms_code': '12345'})
     assert response.status_code == 302
     assert response.location == url_for('main.add_service', first='first', _external=True)
 
+    # make sure the current_session_id has changed to what the API returned
+    with client.session_transaction() as session:
+        assert session['current_session_id'] == str(uuid.UUID(int=1))
+
     mock_check_verify_code.assert_called_once_with(api_user_active.id, '12345', 'sms')
 
 
@@ -57,7 +70,6 @@ def test_should_activate_user_after_verify(
 def test_should_return_200_when_sms_code_is_wrong(
     client,
     api_user_active,
-    mock_get_user,
     mock_check_verify_code_code_not_found,
 ):
     with client.session_transaction() as session:
@@ -77,7 +89,6 @@ def test_verify_email_redirects_to_verify_if_token_valid(
     mock_send_verify_code,
     mock_check_verify_code,
 ):
-    import json
     token_data = {"user_id": api_user_pending.id, "secret_code": 12345}
     mocker.patch('app.main.views.verify.check_token', return_value=json.dumps(token_data))
 
@@ -136,7 +147,6 @@ def test_verify_email_redirects_to_sign_in_if_user_active(
     mock_send_verify_code,
     mock_check_verify_code,
 ):
-    import json
     token_data = {"user_id": api_user_active.id, "secret_code": 12345}
     mocker.patch('app.main.views.verify.check_token', return_value=json.dumps(token_data))