How to improve the test suites exec time?

Hello everybody,

I’m trying to use circleci to run the test suits of my ruby project.

The time that it took to run the whole test suites is about 32 minutes.
When I used the bamboo server to run the test suites, it only took about 9 minutes.

Do you have any suggestion about how to update the circle.yml to improve the speed? Will using cache help and how to use it?

Here’s my circle.yml

Thank you very much