Fest-assert library is obsolete. During fest-assert 2, there was a falling out of owners and assertj became the future direction of fest-assert version 2. In order to migrate there, it's rather simple. Below is URL that describes this and pull request will be made shortly with the change.

http://joel-costigliola.github.io/assertj/assertj-core-migrating-from-fest.html#fest-1.4