Greetings. So we are back with test cases and someone recently told me food > drinks, and why I am telling you this? Because test cases > functions, let's all hail to test case supremacy.
Enough of my nonsensical talk, let's dive straight into this!
JavaScript Testing with Jest
Now, don't get started on I didn't mentioned anything about jest or even javaScript before. That's how it goes here!
What is Jest?
Its an open-source JavaScript testing framework developed by Facebook. It has become a popular choice for testing JavaScript applications, offering a simple and powerful way to ensure the reliability and correctness of your code.
Few Key Features of jest:
Zero Configuration
Fast and Parallelised
Snapshot Testing
Mocking
Built-in Expectations
Support for Asynchronous Testing
Not, going deeper on these features in this blog, might cover them some other time.
Installing Jest
Getting Jest up and running is a breeze. If you haven't installed it yet, run the following command in your project directory:
npm install --save-dev jest
Writing Your First Test
Let's create a simple function and test it. In a file named math.js, write a function:
// math.js
function add(a, b) {
return a + b;
}
module.exports = add;
Now, let's write a Jest test for this function. Create a file named math.test.js:
// math.test.js
const add = require('./math');
test('adds 1 + 2 to equal 3', () => {
expect(add(1, 2)).toBe(3);
});
Running Jest
Run your tests with:
npx jest
Jest will execute your test, and you should see a delightful green check mark indicating success.
What's Next?
Test Cases for Dessert!
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