Use ember mock server for ember test --server

when running ember server, the mocks in server/mocks are served properly, such that they can be used in the tests as well (as the tests are in localhost:4200/tests by default and the api from the mock server is available at localhost:4200/).

However when running ember test --server the mocks are not available which makes tests that rely on those mocks fail. Is this a bug? How to make the mocks available in the test server?