Gain insights into Jest, a versatile testing framework. Learn about fundamental and advanced testing techniques, from unit tests to CI/CD integration, for comprehensive JavaScript application testing.

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Jest is a framework for testing applications developed in JavaScript. It has a well-documented and well-maintained range of tools to run tests in parallel. It is simple and works with projects using Babel, TypeScript, Node, React, Angular, Vue, etc. It works well for both client and server testing. 

This course covers Jest in-depth and is agnostic of any specific JavaScript framework. The course begins with the fundamentals of Jest testing, deconstructing the components of a test and covering how to compose basic unit tests and snapshot tests with Jest correctly. Next, it shows the testing of asynchronous code and the code that relies on external dependencies. Lastly, this course illustrates how Jest testing can effectively integrate into the real-world software development cycle through CI/CD pipeline.

It gives you hands-on experience in setting up Jest, types of testing, testing coverage, mocking, and native tooling depth.

…. To come 

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Mastering Jest: A Complete Guide to Testing

## What is snapshot testing?

**Snapshot testing** is specific to testing client-side code. While other tests are focused on logic, values, and execution, they fail to test the visual aspect of our code past the most basic level. For instance, if we are testing a button and Jest can't find the button, the test will fail. Snapshot testing relies on a stored snapshot of a rendered user interface, which is then used for comparison against the current rendered user interface. Jest flags the differences between the two states, making us aware of changes to our UI.


# What is snapshot testing?

**Snapshot testing** is specific to testing client-side code. While other tests are focused on logic, values, and execution, they fail to test the visual aspect of our code past the most basic level. For instance, if we are testing a button and Jest can't find the button, the test will fail. Snapshot testing relies on a stored snapshot of a rendered user interface, which is then used for comparison against the current rendered user interface. Jest flags the differences between the two states, making us aware of changes to our UI.


Get introduced to testing changes in user interfaces with snapshot testing.

Introduction

Setting Up Jest

Jest Matchers

Writing Unit Tests

Writing Snapshot Tests

Asynchronous Code

Mocking

Mocking External Libraries

Working with Jest Mocks

Setup & Teardown

Test Coverage & CI/CD Pipelines

Test Coverage in Jest

Conclusion

Bonus: Best Practices

Bonus: Resources for Continued Learning

Appendix

Introduction to Snapshot Tests

What is snapshot testing?