React Testing Library - "messageParent" can only be used inside a worker

Question

I'm testinng a react component using the RTL, and everytime I ran a test, I get,

"messageParent" can only be used inside a worker

**Here's the code

describe('Header', () => {
  it('validates header component is rendered', () => {
    const { getByTestId } = render(<Header patientName="Jake Bland" />);
    expect(getByTestId('patient-name')).toHaveTextContent(/^Jake Bland$/);
    expect(getByTestId('dateRange')).toBe(dateRange);
  });
});

Any help on this will be greatly appreciated.

Answer 1

I was having the same issue, and it was caused by calling toBe() or toEqual() on an HTMLElement. So your most likely culprit is here, since getByTestId returns an HTMLElement:

expect(getByTestId('dateRange')).toBe(dateRange);

I fixed my issue by testing against the element's text content instead.

expect(getByTestId('dateRange')).toHaveTextContent('...');