When setting the permisssion to allow inbound numbers the client will call an api endpoint that will set the next avaiable inbound number for the service.

As before the service manager will not be able to change the Text message sender once they have the inbound sms permission.
If the inbound sms permission is turned off the Text message sender setting is once more configurable by the service manager.
The inbound number remains bound to the service, but has "inactive", so that the number can not be used again.

tests/app/main/views/service_settings/test_inbound_sms_setting.py

@@ -8,15 +8,13 @@ from notifications_python_client.errors import HTTPError
 def test_set_text_message_sender(
         logged_in_client,
         mock_update_service,
-        service_one,
-        mock_get_letter_organisations,
-        mock_get_inbound_number_for_service
+        service_one
 ):
     data = {"sms_sender": "elevenchars"}
     response = logged_in_client.post(url_for('main.service_set_sms_sender', service_id=service_one['id']),
-                                     data=data,
-                                     follow_redirects=True)
-    assert response.status_code == 200
+                                     data=data)
+    assert response.status_code == 302
+    assert response.location == url_for('main.service_settings', service_id=service_one['id'], _external=True)
 
     mock_update_service.assert_called_with(
         service_one['id'],
@@ -69,7 +67,8 @@ def test_allow_inbound_sms_returns_400_if_no_numbers_available(
     mock_switch_service = mocker.patch('app.service_api_client.update_service_with_properties')
     mock_activate_inbound = mocker.patch('app.inbound_number_client.activate_inbound_sms_service',
                                          side_effect=HTTPError)
-    logged_in_client.get(url_for('main.service_set_inbound_number', service_id=service_one['id']))
+    logged_in_client.get(
+        url_for('main.service_set_inbound_number', service_id=service_one['id'], set_inbound_sms='True'))
     mock_activate_inbound.assert_called_once_with(service_one['id'])
     assert mock_switch_service.call_count == 2
 
@@ -80,12 +79,13 @@ def test_set_text_message_sender_and_inbound_sms_permission_exists_return_403(
         mocker,
 ):
     service_one['permissions'] = ['inbound_sms']
-    update_service_mock = mocker.patch('app.service_api_client.update_service_with_properties',
-                                       return_value=service_one)
+    mocker.patch('app.service_api_client.get_service', return_value={'data': service_one})
+    update_service_mock = mocker.patch('app.service_api_client.update_service_with_properties')
 
     data = {"sms_sender": "elevenchars"}
     response = logged_in_client.post(url_for('main.service_set_sms_sender', service_id=service_one['id']),
                                      data=data)
+
     assert response.status_code == 403
 
     assert not update_service_mock.called
@@ -105,18 +105,17 @@ def test_turn_inbound_sms_off(
     response = logged_in_client.get(url_for('main.service_set_inbound_number', service_id=service_one['id'],
                                             set_inbound_sms=False))
     assert response.status_code == 302
-    assert response.location == url_for('main.service_set_sms_sender', service_id=service_one['id'])
+    assert response.location == url_for('main.service_set_sms_sender', service_id=service_one['id'], _external=True)
 
     assert app.current_service['permissions'] == []
     mock_deactivate_inbound.assert_called_once_with(service_id=service_one['id'])
+    assert update_service_mock.called
 
 
 def test_set_text_message_sender_and_not_inbound_sms(
         logged_in_client,
         service_one,
-        mock_get_letter_organisations,
-        mocker,
-        mock_get_inbound_number_for_service
+        mocker
 ):
     service_one['permissions'] = []
     update_service_mock = mocker.patch('app.service_api_client.update_service',
@@ -125,9 +124,9 @@ def test_set_text_message_sender_and_not_inbound_sms(
     data = {"sms_sender": "elevenchars"}
     response = logged_in_client.post(url_for('main.service_set_sms_sender', service_id=service_one['id'],
                                              set_inbound_sms=False),
-                                     data=data,
-                                     follow_redirects=True)
-    assert response.status_code == 200
+                                     data=data)
+    assert response.status_code == 302
+    assert response.location == url_for('main.service_settings', service_id=service_one['id'], _external=True)
 
     update_service_mock.assert_called_with(
         service_one['id'],
@@ -145,8 +144,6 @@ def test_set_text_message_sender_validation(
         logged_in_client,
         mock_update_service,
         service_one,
-        mock_get_letter_organisations,
-        mock_get_inbound_number_for_service,
         content,
         expected_error,
 ):

tests/app/main/views/test_service_settings.py

@@ -724,7 +724,6 @@ def test_does_not_show_research_mode_indicator(
     assert not element
 
 
-
 @pytest.mark.parametrize('url, bearer_token, expected_errors', [
     ("", "", "Can’t be empty Can’t be empty"),
     ("http://not_https.com", "1234567890", "Must be a valid https url"),