Should.ml is a little library for writing assertion statements in a
domain-specific language roughly resembling plain English. This makes
lengthy series of assertions (such as in unit tests) a little nicer to read
- example pasted below. Through some mild abuse of objects and operators, I
avoided the need for any preprocessor or syntax extension.

https://github.com/mlin/should.ml
opam update && opam install should

Happy testing!
Mike

Example:

open Should

let int_test_case () =
    let x = 123 in begin
        x $hould # equal 123;
        x $hould # not # equal 0;

        x $hould # be # above 122;
        x $hould # be # at # most 124;

        x $hould # be # within (122,123);
        x $houldn't # be # within (1,3)
    end