Jest

With Jest it’s possible to assert of single or specific arguments/parameters of a mock function call with .toHaveBeenCalled/.toBeCalled and expect.anything(). The full example repository is at github.com/HugoDF/jest-specific-argument-assert, more specifically lines 17-66 ...

To test an Express handler, it’s useful to know how to successfully mock/stub the request and response objects. The following examples will be written both using Jest and sinon (running in AVA). The rationale for this is the following. Jest is a very popular “all-in-one” testing ...

This post goes through some patterns that can be used to unit test ES6 classes. The examples will use Jest module auto-mocking but should be portable to other module mocking libraries (eg. Proxyquire) with some modifications. In “Using ES6 classes for Sequelize 4 models&rdq ...

There’s some nice use-cases for snapshot tests outside of the well-travelled React/Vue UI component ones. In other words, although React and Vue testing with snapshots is pretty well documented, that’s not the only place they’re useful. As a rule of thumb, you c ...

Testing is a crucial part of the software development process. It helps to catch bugs, avoid regressions and to document the behaviour of a piece of software. Express is one of the most widespread libraries for building backend applications in JavaScript. What follows is a summar ...

The trials and tribulations of kicking off an AngularJS -> Vue.js migration AngularJS was pretty groundbreaking. It’s still impressive to this day, packed with a router, an HTTP client, a dependency injection system and a bunch of other things I haven’t necessarily had the p ...