React Testing Library failing test with code 'Font.register...'

[mdodge-ecgrow]

I have several components that are creating PDF documents with this library with custom imported fonts. I am registering the fonts like this:

Font.register({
	family: 'PTSerif',
	format: 'truetype',
	src: PTSerif,
});

Font.register({
	family: 'Raleway',
	format: 'truetype',
	src: Raleway,
});

Well, I am starting to write unit tests for all my code using React Testing Library. And on these components I am getting a failing test with the following error: TypeError: Cannot read properties of undefined (reading 'register') and it highlights the Font.register line. Any ideas how I can get around this?

I did add this import to my test file and did not see any changes in the test results:

import {
	Page,
	Text,
	View,
	Document,
	StyleSheet,
	Canvas,
	Font,
	Image,
} from '@react-pdf/renderer';

Update
So I just tried adding the 'Font' function to this snippet in my test file:

jest.mock('@react-pdf/renderer', () => ({
	PDFViewer: jest.fn(() => null),
	Font: jest.fn(() => null),
}));

And my error changed to: TypeError: _renderer.Font.register is not a function. I tried to change the mocked function to 'Font.register' but my IDE doesn't seem to like that syntax.

[Krzyku]

So Your implementation of Font is a function that returns null.
This should be closer to what you're doing:

jest.mock('@react-pdf/renderer', () => ({
  // ...
  Font: { register: () => null },
}));

For further information, You should visit jest docs
Personally, I would consider if unit tests with mocked PDF make sense.