To start writing tests with Mocha, we first need to install and configure the framework. This chapter will guide you through the installation process, basic configuration, and running your first set of tests.

Prerequisites

Before we start, make sure you have Node.js and npm installed on your system. You can download Node.js from nodejs.org.

Installing Mocha

Mocha is easily installed using npm. There are two ways to install Mocha: globally or locally as a development dependency in your project. Local installation is generally the best practice as it ensures that the project uses the same version of Mocha regardless of the environment.

Local Installation

To install Mocha locally in your project, navigate to your project's root directory in the terminal and run the following command:

sh

This will download Mocha and add it to the development dependencies in your package.json.

Global Installation

If you want to install Mocha globally, you can do so by running:

sh

Configuring Mocha

Project Structure

It is recommended to have an organized project structure to facilitate management of your tests. A typical structure might be:

Test Script Configuration

To simplify running the tests, it is useful to add a test script in the package.json. Open your package.json file and add the following script:

json

This will allow you to run your tests simply by using the command npm test in your terminal.

Writing Your First Test

Test File

Create a test file named example.test.js in the test/ directory.

javascript

Running the Tests

To run the tests, simply navigate to the root of your project in the terminal and execute:

sh

You should see an output in the terminal indicating that Mocha has run the tests. If everything is set up correctly, you should see something like this:

Advanced Configuration

Mocha also allows for more advanced configurations, such as defining a .mocharc.json configuration file to customize Mocha's behavior.

Mocha Configuration File

You can create a configuration file mocharc.json in the root of your project:

json

In this example, we are using Babel to transpile our code before running it.

Conclusion

You have now successfully set up and run your first test with Mocha. In the upcoming chapters, we will explore how to write more complex tests, how to integrate Mocha with other tools, and how to apply best practices to ensure the quality of your code.