My test case makes a checklist of events that I will expect during the test

I am starting the code-under-test, with an injected dependancy back to me

I received a call on the injected dependency
Thinks: I can't just let my test case continue here
I will use the checklist to find out whether it is correct

The call was correct! :-)
Now the checklist tells me how to respond to the call

The code-under-test has completed and I check its output
Test passed! :-)


I say "please start the code-under-test"
I start the code and inject dependency back to me

I say "I received this mock call"
Inside my test case, I check that the call is correct

The call was correct! :-)
I say "please return this value"
I return the mock call

I say "the code-under-test has completed and here is its output"
I check the output
Test passed! :-)