Mocha testing failed due to css in webpack

Question

I'm new to Mocha and I am trying to use it to test a simple React component. The test would pass if the react component doesn't have any CSS styling but throws a syntax error if the tag within the React component contains any className:

Testing.react.js

import React from 'react';

export default class Testing extends React.Component {
  render() {
    return (
      <section>
        <form>
          <input type="text" />
        </form>
      </section>
    );
  }
}

testing.jsx

import {
  React,
  sinon,
  assert,
  expect,
  TestUtils
} from '../../test_helper';

import TestingSample from '../../../app/components/Testing.react.js';

describe('TestingSample component', function(){
    before('render and locate element', function(){
        var renderedComponent = TestUtils.renderIntoDocument(
            <TestingSample />
        );

        var inputComponent = TestUtils.findRenderedDOMComponentWithTag(
            renderedComponent, 'input'
        );

        this.inputElement = inputComponent.getDOMNode();
    });

    it('<input> should be of type "text"', function () {
        assert(this.inputElement.getAttribute('type') === 'text');
    });
})

The test would pass:

> mocha --opts ./test/javascripts/mocha.opts --compilers js:babel/register --recursive test/javascripts/**/*.jsx


  TestSample component
    ✓ <input> should be of type "text"


  1 passing (44ms)

after I added the className inside of the input tag an error shows up:

import React from 'react';
import testingStyle from '../../scss/components/landing/testing.scss';

export default class Testing extends React.Component {
  render() {
    return (
      <section>
        <form>
          <input type="text" className="testingStyle.color" placeholder="Where would you like to dine" />     
        </form>
      </section>
    );
  }
}

Test result:

SyntaxError: /Users/../../../Documents/project/app/scss/components/landing/testing.scss: Unexpected token (1:0)
> 1 | .color {
    | ^
  2 |   color: red;
  3 | }

I've searched online but no luck so far. Am I missing something? Please help me out or point me to the right direction would be greatly appreciated. I'm currently using:
Node Express Server
React
React-router
Webpack
Babel
Mocha
Chai
Sinon
Sinon-Chai

Answer 1

Since you're using webpack, use null-loader to load null when webpack encounters a required CSS/LESS/SASS/etc file in your components. Install via npm and then update your webpack config to include the loader:

{
    test: /(\.css|\.less|.\scss)$/,
    loader: 'null-loader'
}

Obviously this will prevent you from loading CSS in your actual application, so you'll want to have a separate webpack config for your test bundle that uses this loader.