What's the idiomatic way to test functions which return callables


Let’s say a function returns a callable, how to unit test it in kotlin.test (multi-platform code)?
In JVM I can just use assertEquals, but it won’t work in JS since the callable is represented differently.
I can use the callable and test it’s output on some receiver, but for obvious reasons it’s not a bulletproof solution. Is there some idiomatic way in kotlin.test to unit test callables?