[Contributing] How do I test matcher outputs?

[SevenOutman]

Hi there, I want to contribute some new matchers but don't see how to test the outputs.

For example, I want .toHaveApples() output like below in some cases:

Found some apples but they don't belong to you.

I looked in the codebase but only found tests for whether matchers pass/fail correctly, not for outputs.

[SevenOutman]

Found out myself.

expect(() => {
  expect(thing).toHaveApples();
}).toThrowError("expected output");