4. Introduction to Jest

Question 1

What are the six common Jest pitfalls?

Answer 1

1. Tests are not written
2. No integration with version control
3. Jest is not integrated into devs’ workflow
4. Devs skip tests instead of fixing them
5. No integration with deployment/CI
6. Tests do not protect against critical errors

Question 2

What is Jest?

Answer 2

Jest is a modern and widely adopted test runner that is built on top of Mocha and Jasmine. It’s developed by the React team.

Question 3

What can be said about Jest versioning?

Answer 3

Jest tends to vary in minor yet significant ways from version to version. Being aware of which Jest version you’re working with is one of the best skills to prevent surprises and unexpected bugs.

Question 4

What can be said about Jest in relation to Mocha?

Answer 4

Jest is built on top of Mocha and it is similar to Mocha but has a ton of extra features such as spies and snapshots.