Mock dependency in ELM

In every elm file, dependencies to be imported are declared at the top. Is there a way, while testing the application, to mock a dependency?

For example, suppose I have an application using the HTTP module to make an ajax request. When I test my module, I would like to avoid to make the actual ajax request, but I'd like to have a mocked HTTP module which will return a fake response just for the sake of testing.

How could I do this?