https://sairam.dev/tags/tests/ Recent content in tests on Sai Ram's Blog Hugo -- gohugo.io en-us © 2020. All rights reserved. Tue, 11 Apr 2017 22:00:00 +0530 https://sairam.dev/post/2017-04-11-identifying-bad-tests/ Tue, 11 Apr 2017 22:00:00 +0530 https://sairam.dev/post/2017-04-11-identifying-bad-tests/ Look at this code Rails FactoryGirl definition for a regular user class FactoryGirl.define do factory :user do first_name "John" last_name "Doe" subscription_end_date Date.parse("2019-01-01") end end Does not look harmful. This is a base model. When your other spec files start using it, everything will work fine when you evaluate the subscription_end_date with other fields, but, exactly after 2019-01-01, on 2nd Jan 2019, the tests dependent on this value will start failing.