Generally you shouldn’t really be using integration tests for TDD, but it’s totally possible to write your tests in a way where the dependency supplied is talki

Generally you shouldn’t really be using integration tests for TDD, but it’s totally possible to write your tests in a way where the dependency supplied is talking to a real system in one scenario and in another scenario is talking to a system with mocked responses - or any sort of level of depth in between. However, I wouldn’t start out writing a system like this (aka TDD). From my experience, the best tested software looks like this as the end result and the design of the software itself has been forged in the same furnace. Not sure if that completely makes sense, since some of these concepts are from functional programming and I never know what is totally foreign or totally obvious.