Testing behaviour of classes with deep nested dependencies

I am testing system behaviour with Behat (the domain, not web) and i want to test behaviour that uses UserService class. UserService takes UserRepository (Interface) as an argument. Should i create the UserService object in the context or should i take it from some dependency injection container (which i currently don't have since i want to model the domain first)? Or should i maybe create a factory to construct the UserService?

The problem here is, that there may be multiple implementations of UserRepository and i want to test the one the system uses (hence taking UserService from DI container).