test.js

// MockedError Provider

import React from 'react';
import { ApolloProvider } from '@apollo/react-hooks';
import { InMemoryCache } from 'apollo-cache-inmemory';
import { ApolloLink, Observable } from 'apollo-link';
import { ApolloClient } from 'apollo-client';
import { GraphQLError } from 'graphql';

type Props = {
  errors: Readonly<GraphQLError[]>;
  children: JSX.Element;
};

const MockedErrorProvider = ({ errors, children }: Props) => {
  const link = new ApolloLink(() => new Observable((observer) => {
    observer.next({
      errors,
    });
    observer.complete();
  }));

  const client = new ApolloClient({
    cache: new InMemoryCache(),
    link,
  });

  return (
    <ApolloProvider
      client={client}
    >
      {children}
    </ApolloProvider>
  );
};

export default MockedErrorProvider;


// Usage

it('should render the advise screen when has a network error', () => {
    render(
      <AuthoMockedErrorProvider
        errors={[new GraphQLError(CONSTANTS.ERROR_MESSAGES.NETWORK_FAILED_CONNECTION)]}
      >
        <ThemeProvider
          theme={dark}
        >
          <News
            navigation={navigation}
          />
        </ThemeProvider>
      </AuthoMockedErrorProvider>,
    );

    act(() => {
      jest.runAllTimers();
    });
  });

// Verifying the error

if (error && error.message === CONSTANTS.ERROR_MESSAGES.NETWORK_FAILED_CONNECTION) {
  // handle the specified error
}