CODEWITHSUNDEEP
reactjsunit-testingjestjsreact-testing-libraryjest-dom
napster499
napster499

Reputation: 69

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

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.

Upvotes: 6

Views: 2625

Answers (4)

Fasunle Kehinde Hussein
Fasunle Kehinde Hussein

Reputation: 15

I had the same bug but I was able to fix it by importing '@testing-library/jest-dom' as follows in my test file:

import '@testing-library/jest-dom'

It turned out that the package above is a peerDependency for '@testing-library/react'. Thus the error.

Upvotes: 0

JPollock
JPollock

Reputation: 3558

I ran into this error while testing to see if a <select> had the right number of options, when using this:

expect(container.querySelectorAll('option')).toBe(2);

@testing-library/react must be trying to do something strange to get the length of the HTML collection, I have. So I added .length to the query:

expect(container.querySelectorAll('option').length).toBe(2);

All was well.

Upvotes: 0

Eric
Eric

Reputation: 353

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('...');

Upvotes: 17

John
John

Reputation: 1665

Hi I had the same issue after spending some time googling around i found this: github issues forum

it turned out that this issue is caused by node12 version i downgraded my one to version 10 and everything worked i have also upgraded to version 14 and that also works.

check what is yours node version in ur terminal:

  1. node -v if (version 12) upgrade it!
  2. nvm install v14.8.0 (something like this or the leates one)
  3. nvm use v14.8.0 (or any other version you may wish to install that is above 12)

hopefully this helps

Upvotes: 0

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