react-native-firebase/jest.setup.js

import * as ReactNative from 'react-native';

jest.doMock('react-native', () => {
  return Object.setPrototypeOf(
    {
      Platform: {
        OS: 'android',
      },
      NativeModules: {
        ...ReactNative.NativeModules,
        RNFBAppModule: {
          NATIVE_FIREBASE_APPS: [
            {
              appConfig: {
                name: '[DEFAULT]',
              },
              options: {},
            },
          ],
        },
        RNFBPerfModule: {},
      },
    },
    ReactNative,
  );
});