testing-async-using-done.test.js

/* src/__tests__/helpers/index.test.js */
import { isEarlierThanNow, fetchFakeAPIData } from '../../helpers';

// ...

test('fetchFakeAPIData, when requesting an animal, responds with a dog', (done) => {
  // Arrange 
  const testRequest = { animal: true };

  // Act
  fetchFakeAPIData(testRequest).then(({ animal, name }) => {
    // Assert  
    expect(animal).toBe('Dog');
    expect(name).toBe('Charlie');
    done();
  })
});

test('fetchFakeAPIData, when not requesting an animal, responds with an error message', (done) => {
  // Arrange 
  const testRequest = { random: true };

  // Act
  fetchFakeAPIData(testRequest).catch(({ error }) => {
    // Assert  
    expect(error).toMatch(/Did not find species/i);
    done();
  });
})