Checking sets

Checking the whole set

You can use just to apply Midje's notion of extended equality to an entire set:

(fact "`just` provides extended equality to set equality"
  #{3 8 1} => (just odd? 3 even?))

Notice that Midje goes to some effort not to commit too early to a match. For example, suppose it decided that odd? matched 3. Then there would be no way for the remainder to match. Rather than failing, Midje will backtrack and find the match (`odd? => 1, 3 => 3, even? => 8).

If you require that there be a specific number of elements, all of which share the same property, you can use the n-of family of checkers:

(fact "checking properties of known number of elements"
  #{1 3 5} => (three-of odd?))

If you don't care about the number of elements, use has:

(fact "number irrelevant"
  #{1 3 5} => (has every? odd?))

Checking a subset

When you want to work with a subset of the original set, use contains. Here's an example that doesn't take advantage of extended equality:

(fact "subsets of literal values"
  #{1 2 3} => (contains 3))

Here's one that does:

  (fact "subsets of checkers"
    #{1 2 3} => (contains odd? even?)))