$empty

The $empty matcher checks that an object, array, or string has length 0.

Because of Capti's implicit matching, you cannot simply write something like this:

  expect:
    body:
      comments: []

The goal here is to assert that the comments array is empty, however because of implicit matching, this will match any number of comments.

To properly assert that there are no comments in this array, you can use the $empty matcher instead.

  expect:
    body:
      comments: $empty

You can also use $empty to match empty objects or strings. Using $empty is identical to writing $length 0.