Annoyingly, the behaviour of `bash -e` changed between version 3 and version 4, so in e.g. Ubuntu 12.04 this will fail. So, in *GNU bash, version 4.2.24(1)-release (x86_64-pc-linux-gnu)* `bash -e` will terminate a script if commands in subshells (using parenthesis) exit with a non-zero status, wheras on the OSX default (*GNU bash, version 3.2.48(1)-release (x86_64-apple-darwin12)*) this is not the case. I'm think we should just mark this test a **WIP** and move on.