Expo SDK 52 expo-font's isLoaded method no longer compatible with RNTL's render method, @expo/vector-icons depends on this

[timheilman]

Describe the bug

Upgrading from Expo SDK 51 to Expo SDK 52 causes expo-font's major version to move from 12 to 13. This causes a failure with the react-native-test-renderer's render method whenever expo-font's isLoaded method is called:

    TypeError: loadedNativeFonts.forEach is not a function

      3 |
      4 | export default function App() {
    > 5 |   const robotoLoaded = isLoaded("Roboto");
        |                                ^
      6 |   return (
      7 |     <View style={styles.container}>
      8 |       <Text>{robotoLoaded}</Text>

      at forEach (node_modules/expo-font/src/memory.ts:21:23)
      at isLoaded (node_modules/expo-font/src/Font.ts:27:24)
      at App (App.js:5:32)

In particular, this impacts @expo/vector-icons rendering, including in react-native-paper, which has had an issue filed in that repo.

I'm not sure whether the fix to this needs to be made in expo-fonts or in react-native-testing-library, or elsewhere, but I'm starting here.

Expected behavior

Using @expo/vector-icons, which itself calls expo-font's isLoaded method, will not cause react-native-test-renderer's render method to fail with the above exception.

Steps to Reproduce

I've made a minimal reproduction. A simple npm install then npm test will demonstrate the issue.

Screenshots

This is purely a testing issue, no screenshots.

Versions

➜  react-native-testing-library-expo-icons-issue git:(master) npx envinfo --npmPackages react,react-native,react-test-renderer,@testing-library/react-native                                 <region:us-west-2>
Need to install the following packages:
[email protected]
Ok to proceed? (y) y

  npmPackages:
    @testing-library/react-native: ^12.8.1 => 12.9.0
    react: 18.3.1 => 18.3.1
    react-native: 0.76.3 => 0.76.3
    react-test-renderer: ^18.3.1 => 18.3.1

[timheilman]

Here is a workaround, from jest setup file (before env):

jest.mock("expo-font", () => {
  const module: typeof import("expo-font") = {
    ...jest.requireActual("expo-font"),
    isLoaded: jest.fn(() => true),
  };

  return module;
});