Jasmine vs Jest: What are the differences?

Jasmine and Jest are popular testing frameworks used in JavaScript development. While they share some similarities, there are several key differences between them that set them apart. Here are six specific differences:

1. Installation: Jasmine requires manual installation as a standalone library, which involves downloading and adding it to your project. On the other hand, Jest comes pre-packaged with Create React App and can be easily integrated into your project without any additional installation steps.

2. Syntax: When it comes to syntax, there are notable differences between Jasmine and Jest. Jasmine uses a more traditional and verbose syntax with nested describe and it blocks, whereas Jest provides a more streamlined and concise syntax with methods like test and expect.

3. Mocks and Spies: While both frameworks allow you to create mocks and spies to test function behavior, Jest provides built-in support for mocks and spies out of the box. Jest's jest.fn() allows you to easily mock functions and track their calls, whereas in Jasmine, you need to use separate libraries like Sinon or Jasmine-SpyObj to achieve similar functionality.

4. Snapshot Testing: Snapshot testing is a powerful feature offered by Jest that allows you to capture and compare the output of your components or functions with previously saved snapshots. This can be particularly useful when testing UI components. Jasmine, on the other hand, does not have built-in support for snapshot testing, although it can be achieved with additional libraries.

5. Parallel Testing: When it comes to parallel testing, Jest has a distinct advantage over Jasmine. Jest is designed to run test suites in parallel, making it much faster when you have a large number of tests. Jasmine, on the other hand, does not have built-in support for parallel testing and runs tests sequentially.

6. Code Coverage: Both Jasmine and Jest provide code coverage reports, but Jest's code coverage tools are more advanced and powerful. Jest's coverage report includes detailed information such as line, statement, and branch coverage, making it easier to identify areas of your code that need further testing. Jasmine's coverage report is relatively simpler and provides less detailed information.

In summary, Jasmine and Jest have some similarities but also significant differences. Jest offers a simpler installation process, a more streamlined syntax, built-in support for mocks and spies, snapshot testing, better parallel testing, and more advanced code coverage tools. Consider your specific project requirements and preferences to choose the framework that best suits your needs.