Why rails 4 tests does not reset db

I'm using Ruby 2.3.0 and Rails 4.2.7. I'm also using minitest ( ActionController::TestCase ) and these gems

gem 'capybara', '~>2.7.1'
gem 'poltergeist', '~>1.9.0'
gem 'minitest-rails-capybara', '~>2.1.2'

I was under the impression that everytime 'rake test' is called, the database is dropped and created with schema.rb (as it happens in all my other projects)

But with this project it doesn't do this (If i manually change something on the test db, it stay that way between test)

Is this normal? What could be the cause?