CSS Modules not working as expected in tests with Jest and Enzyme, using create-react-app

I am using CSS modules in a CRA app. My component looks like this:

import HeaderStyles from './Header.module.scss';

const Header: FunctionComponent<HeaderProps> = ({
// Props
}) => (
  <div className={HeaderStyles['header-container']}>
  // Some other stuff
)

My test looks like this:

    const component = shallow(
      <Header />
    );

    expect(component.find('.header-container')).toBeTruthy();

I would expect it to fail since the class name should be something different since I'm using CSS Modules. Am I missing something here?