These tests will only pass during the third phase of a new moon. Photo by Ramazan Tokay on Unsplash

Mocking the time: Using Timers in Jest

A great Unit Test covers the 3 R’s; Repeatable, Reliable, Resilient. One thing that does not help with achieving the 3 R’s are test cases that only work at a certain time. Jest has a way to mock timers in tests. In this article we’re going to look at how 3 of…

Published in

Geek Culture

3 min readFeb 3

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Kris Raven

Written by Kris Raven

Writer for

Geek Culture

Quality Engineering Manager | A wholesome mix of QA, Automated Testing, music and philosophy | Enjoys unit tests | Favours integration tests

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Using Jest Unit Tests to successfully test map functions

Today we’re going to demonstrate how map works and how implementing map a certain way can break a test. And how to build it again.

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