A test suite is a collection of tests that you can run against a piece of software. The goal is for these tests to catch any errors in your software before you make it available to the end user. A good test suite is one that doesn’t take long to run, and if all the tests are passing, provides you with confidence that your software is working as expected. If a good test suite catches a bug, it will return feedback that can help you identify the source of the issue, and help you resolve it. A bad test suite may take a long time to run and/or, if passing, won’t provide you with confidence that your software is working as expected. If a bad test suite catches a bug, it may not return helpful feedback or be a false negative, which will make it challenging to identify the source of the issue. In this article, you will learn about six characteristics of a good test suite, originally enumerated by Josh Steiner and Joël Quenneville Testing Rails. If you keep these characteristics in mind as you write tests, you improve the chances that your test suite will run efficiently and it provides you with confidence that your software is working as expected.