Rake test swallowing errors

I am trying to write a rake commit task so that before I commit
changes to svn it executes my unit tests. I have a failing unit test,
but the test:units is not raising the exception so my commit task
still executes.


task :commit => :test do
#should not reach because I have a failing test, but the test task
passes anyway and executes this
#subversion commit done here