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GitHub User: rcillo
This bug has been fixed in Rails 4.
It seems that one of the things rspec-rails does is to add 'test:prepare' as a dependency to the test task. Commented it in the activerecord databases.rake to check and it's accountable for 2 seconds here.
Still cannot figure out where the other 2 seconds goes.
Why running tests with rspec is faster than with rake? What's rake doing unnecessarily?