Export function expect()

[mllg]

In order to write custom expect functions for checkmate I jumped through many hoops to talk to the reporter (or I did something really stupid). Same holds for the upcoming testthat version for which I currently prepare a new checkmate release. Exporting expect() would greatly simplify this.

[hadley]

Agreed - I'm not in love with the API, but this will at least let you easily create your own expectations.