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Jasmine vs Mocha: What are the differences?
Introduction
Jasmine and Mocha are both popular JavaScript testing frameworks used for testing JavaScript applications. While they both serve the purpose of writing efficient and effective unit tests, there are key differences between the two.
Test Syntax: Jasmine uses a behavior-driven development (BDD) syntax, which focuses on writing tests in a more human-readable format. On the other hand, Mocha uses a more traditional syntax, allowing developers to use any style of testing (BDD, TDD, or even a combination of both). This provides more flexibility in writing tests based on personal preferences and project requirements.
Assertions: Jasmine provides its own built-in assertion library, offering a wide range of assertion functions. This eliminates the need for an external library for assertions. Mocha, on the other hand, does not include an assertion library by default. It provides a testing framework and hooks for integrating external assertion libraries like Chai or should.js. This allows developers to choose their preferred assertion library and customize it to their needs.
Asynchronous Testing Support: Mocha has built-in support for asynchronous testing, making it easier to write tests for code that involves asynchronous operations. It supports testing promises, callbacks, and other asynchronous patterns out of the box. Jasmine also supports asynchronous testing but requires the use of additional functions like
done()
orasync/await
to handle asynchronous operations.Test Runner: Mocha provides a test runner that can be integrated with various build systems and frameworks, allowing developers to execute tests in different environments (e.g., browser, Node.js). Jasmine, on the other hand, includes its own test runner, making it easier to set up and execute tests without additional configuration.
Mocking and Spies: Jasmine includes built-in support for mocking functions and creating spies, which are objects that track function calls and return values. This makes it easier to stub or spy on functions during tests. Mocha does not have built-in features for mocking or spying, but it can be paired with other libraries like Sinon.js to achieve similar functionality.
Community and Ecosystem: Both Jasmine and Mocha have active communities and a wide range of plugins and extensions available. However, Mocha has a larger ecosystem due to its flexibility and compatibility with different assertion libraries and test runners. This makes it easier to find community support, examples, and integrations for specific use cases.
In summary, Jasmine and Mocha differ in test syntax, assertion libraries, asynchronous testing support, test runner, mocking capabilities, and community size. These differences make them suited for different preferences and project requirements in JavaScript testing.
We were able to combine multiple tools with Jest and React Testing Library (e.g. sinon, enzyme, chai). Jest has powerful cli options and increased performance including from parallel testing processes. Migrating was reasonably straight forward as there is a code transformation script to do most of the leg work. Jest's documentation is excellent.
We use Mocha for our FDA verification testing. It's integrated into Meteor, our upstream web application framework. We like how battle tested it is, its' syntax, its' options of reporters, and countless other features. Most everybody can agree on mocha, and that gets us half-way through our FDA verification and validation (V&V) testing strategy.