pyhamcrest_metamatchers

So that you can match your matchers with matchers, while you are writing matchers!

But seriously: Hamcrest and hamcrest-style matchers help in writing modular and reusable tests, but for that the matchers themselves must be reliable. Now you can develop your own custom matchers and be sure that they are. All you need to do is to test them using metamatchers.

• Code Documentation
  • matches
  • doesnt_match
  • with_description
  • with_mismatch_description

The goal of this project is to write a number of utility entities to facilitate the development of proper hamcrest style matchers.

For now we have a metamatcher, that is a matcher that can check that a matcher under development behaves properly, that is it matches whatever it is supposed to match, and it doesn’t match whatever it isn’t suppsed to, and that it produces the correct descriptions and mismatch descriptions. Here is a code example to that effect:

def test_is_twice_as_big_as(...)
    assert_that(
        is_twice_as_big_as(2),
        matches(4).with_description("An int twice as big as <2>")
    )

def test_is_twice_as_big_as_not_matching(...)
    assert_that(
        is_twice_as_big_as(2),
        doesnt_match(7)\
            .with_description("An int twice as big as <2>")\
            .with_mismatch_description("was <7>")
    )