How To Test Canvas Js

Canvas JS is a robust library that enables developers to create graphics using JavaScript and the HTML5 canvas element. Like any other library or code, it is crucial to conduct thorough testing to guarantee the proper functioning of your applications. This article will walk you through the steps of testing Canvas JS.


Testing is a crucial part of software development. It helps to ensure that your code is working as expected, that it is robust and reliable, and that no bugs or errors have been introduced during the development process.


Before you can start testing, you will need to include the CanvasJS library in your project. You can do this by adding the following script tag to your HTML file:

Once the library is included in your project, you can start creating your tests.

Creating Tests

There are many ways to test JavaScript and CanvasJS, but one of the most common methods is using a testing framework like Jest. Jest is a comprehensive JavaScript testing framework that will allow you to write tests for your CanvasJS code.

To install Jest, you can use npm (Node Package Manager) with the following command:

npm install --save-dev jest

After installing Jest, you can create a new .test.js file in your project. This is where you will write your tests. For example, if you have a file named app.js, you can create a new file named app.test.js.

In your test file, you can write the tests. Here is an example of a simple test:

test("Test if Canvas is working", () => {
    const canvas = document.createElement('canvas');

    let chart = new CanvasJS.Chart(canvas, {
    title: {
        text: "Test Chart"
    data: [{       
        type: "line",
        dataPoints: [
            { x: 1, y: 450 },
            { x: 2, y: 414 },
            { x: 3, y: 520 },
            { x: 4, y: 460 },
            { x: 5, y: 450 }



This test first creates a new canvas element, then creates a new CanvasJS chart, renders it, and finally checks if the chart has been defined.

Running Tests

After you have written your tests, you can run them using the Jest command in your terminal:

npx jest

Jest will automatically run all test files in your project and provide a summary of the results. It will also show any errors or failed tests, making it easy to identify and fix issues.


Testing is an essential part of any software development process, and CanvasJS is no exception. Using a testing framework like Jest can make the process much easier and more efficient. By writing and running tests for your CanvasJS code, you can ensure that your charts and graphics are working correctly and that your application is robust and reliable.