Add a unit test to check if it broke any hooks

This actually checks that all hooks are arrays.  They all should be and
we accidentally set one of them to a string a few commits ago.  It is easy
to miss the lack of a [] in the hooks definition.  This makes sure we
don't.

Change-Id: I62daf390064949b0c07b221581064120d1c9c72c
Merge "Add a unit test to check if it broke any hooks"