not matcher and calling function multiple times

[adamniedzielski]

Thank you for the amazing library - I'm a happy user! I found one issue with how the "not" matcher behaves when the function is called multiple times. Please, take a look:

let roll = td.function();
roll(1);
td.verify(roll(td.matchers.not(1)));

This works as expected - the test fails with:

Unsatisfied verification on test double.

              Wanted:
                - called with `(not(1))`.

              But was actually called:
                - called with `(1)`.

However this one does not fail the test:

let roll = td.function();
roll(4);
roll(1);
td.verify(roll(td.matchers.not(1)));

I guess that the problem here is that one function call ("4") satisfies the matcher. I wonder whether the "not" matcher should mean "none of the calls equal" or "not every call equals". What do you think?

[searls]

Yeah, you diagnosed the issue you ran into here. My recommendation (since it should be unusual that a collaboration test should intentionally make a test double blow up) would be to treat the explosion as a stubbing and not a verification.

Reason being: verifying something did not happen isn't much of a specification at all (surely there are millions of things your subject under test doesn't do, but they don't all warrant an assertion)

Try this instead:

let roll = td.function();
td.when(roll(1)).thenThrow(new Error('woah do not roll a 1'))

roll(1);

[adamniedzielski]

@searls Your reasoning makes sense. Thank you very much for the suggestion.