Custom matchers

Custom matchers are created with the sinon.match factory.

The test function takes a value as the only argument. It must return true, when the value matches the expectation and false otherwise.

<!-- TODO: figure out if the second argument (message) is ever used in sinon, or only in sinon.assert project, if that's true, remove support for second argument in sinon > The message string is used to generate the error message in case the value does not match the expectation. -->

<<< ../../.vitepress/tests/docs/matchers/custom-matchers.test.js