Testing React components

Depending on the complexity of your components and their purpose, it might be advisable that you implement specific unit tests for them. This ensures the component behaves according to specification for every defined scenario and property.

Unit testing

Unit testing is a software development technique by which developers write automatic tests that verify that the smallest testable units of an application (called units) behave according to its design requirements.

Let us see a practical example by implementing a test for the CompleteChip component. In the Implementing a Task Edit dialog section in Chapter 9, Creating the Main Application, we created this custom component that renders the completion date of the provided task, or nothing if the provided task is not completed. To implement the test for this component, we’ll start by creating a new CompleteChip.test.js file in the src/tasks directory.

Test file naming

By default, Jest, with...