Jest Expect.assertions（）方法在异步函数上失败

Question

我正在尝试使用Jest测试提取调用，并且正在使用在教程中看到的expect.assertions()方法。本教程使用的示例当前是fetchUser()对象中的方法testingFunctions。

唯一的区别是fetchUser()和fetchUser3()是前者使用axios。

我从测试中得到的错误是： Expected one assertion to be called but received zero assertion calls.

const testingFunctions = {
  fetchUser: () =>
    axios
      .get("https://jsonplaceholder.typicode.com/users/2")
      .then(response => response.data)
      .catch(err => "invalid fetch"),
  fetchUser3: () => {
    fetch("https://jsonplaceholder.typicode.com/users/3")
      .then(response => response.json())
      .catch(err => "Oh no");
  }
};

test('should fetch and return an object with name of "Clementine Bauch"', () => {
  expect.assertions(1);
  return testingFunctions.fetchUser3().then(data => {
    expect(data.name).toEqual("Clementine Bauch");
  });
});

有什么想法吗？