@Chattered, thanks for your PR! By analyzing the history of the files in this pull request, we identified @peti, @acowley and @bennofs to be potential reviewers.

Please report this issue upstream and, if possible, add the URL of the appropriate ticket in a comment next to the override.

Though I had to jail break it, haskellPackages.pipes-binary built fine for me on current Nixpkgs so doesn't look to me like there's a problem with the test suite --- at least not for our current default haskell package set.