setupJest.js

const { Response, Headers, Request } = require('whatwg-fetch');

global.Response = Response;
global.Headers = Headers;
global.Request = Request;
global.console = {
  log: () => {},
  warn: () => {},
};
global.fetch = require('jest-fetch-mock');

jest.mock('react-native', () => {
  const items = {
    '@login:response': `{"nickname":"marco.perazzetta"}`,
  };
  return ({
    AsyncStorage: {        
      setItem: jest.fn((item, value) => {
        return new Promise((resolve, reject) => {        
      items[item] = value;
          resolve(value);
        });
      }),
      multiSet:  jest.fn((item, value) => {
        return new Promise((resolve, reject) => {
      items[item] = value;
          resolve(value);
        });
      }),
      getItem: jest.fn((item, value) => {
        return new Promise((resolve, reject) => {
          resolve(items[item]);
        });
      }),
      multiGet: jest.fn((item) => {
        return new Promise((resolve, reject) => {
          resolve(items[item]);
        });
      }),
      removeItem: jest.fn((item) => {
        return new Promise((resolve, reject) => {
          resolve(delete items[item]);
        });
      }),
      getAllKeys: jest.fn((items) => {
        return new Promise((resolve) => {
          resolve(items.keys());
        });
      })
    },
    NativeModules: {
      RNDocumentPicker: () => {}
    },
    Dimensions: {
      get: jest.fn(() => ({
        width: 0,
        height: 0,
      }))
    },
    Platform: {
      OS: jest.fn(() => 'android'),
      version: jest.fn(() => 25),
    },
    Easing: {
      bezier: () => {},
    },
    View: () => 'View',
    ViewPropTypes: ({
      propTypes: {
        style: {}
      },
    }),
    Text: ({
      propTypes: {
        style: {}
      },
    }),
    TouchableNativeFeedback: () => 'TouchableNativeFeedback',
    TouchableOpacity: () => 'TouchableOpacity',
    StyleSheet: {
      create: () => ({})
    },
    Animated: {
      createAnimatedComponent: () => {}
    },
    requireNativeComponent: () => {}
  });
});

jest.mock('react-native-fetch-blob', () => ({
  DocumentDir: () => {},
}));