How can get the classname by using React testing library get by classname method and Jest?
I’m new to JavaScript testing and working in a new codebase using Jest and React Testing Library. I need to write a test that verifies a specific className on an element. The test renders a <Button> component with a variant prop, and I want to ensure that the rendered element has a className equal to this variant.
Here’s my current test setup:
it('Renders with a className equal to the variant', () => {
const { container } = render(<Button variant="default" />);
// Need to check for className here
});
I’ve searched for a way to check for className similar to Enzyme’s hasClass but haven’t found a direct equivalent in React Testing Library. How can I achieve this using React Testing Library and Jest?
Hey there! With my extensive experience in React testing, I can say that React Testing Library get by className can be quite handy. You can easily check for the presence of a className on an element by accessing its className
property or using the classList
API, just like you would in a browser environment.
Here’s how you can do it:
// Access className directly
const { container } = render(<Button variant="default" />);
expect(container.firstChild.className).toBe('default');
// Using classList API
expect(container.firstChild.classList.contains('default')).toBe(true);
If you find yourself frequently checking for classes, you can simplify your tests by adding jest-dom
to your project. With jest-dom
, you can use more expressive assertions like toHaveClass
:
// Using jest-dom's toHaveClass matcher
expect(container.firstChild).toHaveClass('default');
This approach leverages familiar browser APIs and integrates well with Jest, making your tests more intuitive and readable.
Absolutely, Madhurima! Building on your point, you can further streamline this process using React Testing Library get by className method and Jest. Here’s a refined way to achieve this:
Using toHaveClass
from jest-dom
:
import '@testing-library/jest-dom/extend-expect'; // Import jest-dom for extended matchers
import { render } from '@testing-library/react';
import Button from './Button'; // Import your Button component
it('Renders with a className equal to the variant', () => {
const { getByRole } = render(<Button variant="default" />); // Render the component
// Assert using toHaveClass matcher
expect(getByRole('button')).toHaveClass('default');
});
This method makes your assertions more readable and concise, leveraging the power of jest-dom
with React Testing Library get by className.
Great insights, Dipen! To add a bit more depth, you can also directly use the classList
API with React Testing Library get by className to check for the presence of a class:
import { render } from '@testing-library/react';
import Button from './Button'; // Import your Button component
it('Renders with a className equal to the variant', () => {
const { getByRole } = render(<Button variant="default" />); // Render the component
const buttonElement = getByRole('button'); // Get the button element
// Check className using classList API
expect(buttonElement.classList.contains('default')).toBe(true);
});
These methods give you a robust way to verify that the rendered <Button>
component has the correct className based on the variant
prop, using React Testing Library get by className and Jest.