Jest Testing
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what is Jest ?
Jest is an open-source testing framework built on JavaScript, designed majorly to work with React and React Native based web applications. Often, unit tests are not very useful when run on the frontend of any software. This is mostly because unit tests for the front-end require extensive, time-consuming configuration. This complexity can be reduced to a great extent with the Jest framework.
Why we use Jest ?
- Zero configuration required.
- Fast: Jest tests run in parallel – this in turn greatly reduces the test execution time.
- Built-in code coverage: Jest supports code coverage out of the box – this is a very useful metric for all CI-based delivery pipelines and overall test effectiveness of a project.
- Isolated and sandboxed tests: Each Jest test runs in its own sandbox, which ensures no two tests can interfere or impact each other.
- Powerful Mocking support: Jest tests support all types of mocking – be it functional mocking, timer mocking, or mocking individual API calls.
- Support snapshot testing: Snapshot testing is relevant from the React perspective. Jest supports capturing a snapshot of the react component being tested – this can validate with the component’s actual output. This greatly helps in validating the component’s behavior.
- Powerful, interactive CLI
