checkable arrows - eunmin/Midje GitHub Wiki

=>

The claim checks out only if extended equality produces a truthy value.

(fact (nth-prime 100) => odd?)

=not=> or =deny=>

The claim checks out only if extended equality does not produce a truthy value.

(fact (nth-prime 100) =not=> even?)

=expands-to=>

The left-hand side is macroexpanded and compared to the right-hand side:

(fact (when true 3) =expands-to=> (if true (do 3)))

Note that neither side is quoted.

=future=>

Acts like a future fact in that it produces a "WORK TO DO" message. This is useful when you've got most of the claims in a fact working, but have to defer finishing one or a few.