Rails full test in vagrant is too slow in my laptop. Did I do something wrong?

I am trying to contribute something in rails.
For the first step, I setup rails-dev-box and configured rsync.

After that I ran my first rails test.

$>bundle exec rake test

Everything looks fine except the test time.

It took more than an hour and I stopped it manually.

I wonder how other people do the full test while developing rails.

Is there any way to speed up the full test or should I test only particular component?

Please help me to go one step forward for contributing to rails community.

Thanks in advance.

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