How to find how long my rake task is taking

I am using Rails 3.0.10 . I am using mac.

I tried this

time  rake spec/models/user_spec.rb

Then I tried

time (rake spec/models/user_spec.rb)

This one took longer but I did not see my test output.

What is the right way to figure out how long my rake is taking.

You should be able to time any command using 'time' and run your single test directly using the ruby interpreter:

time ruby spec/models/user_spec.rb