如何在Jest中测试抛出异常的类型 [英] How to test type of thrown exception in Jest

问题描述

我正在使用一些代码，我需要测试函数抛出的异常类型（是TypeError，ReferenceError等）。

I'm working with some code where I need to test type of exception thrown by function (Is it TypeError, ReferenceError etc.).

我当前的测试框架是AVA，我可以测试它作为第二个参数 t.throws 方法，就像这里：

My current testing framework is AVA and I can test it as a second argument t.throws method, like here:

it('should throw Error with message \'UNKNOWN ERROR\' when no params were passed', (t) => {
  const error = t.throws(() => {
    throwError();
  }, TypeError);

  t.is(error.message, 'UNKNOWN ERROR');
});

我开始将测试改写为Jest，但却找不到如何轻松做到这一点。甚至可能吗？

I started rewriting my tests to Jest and couldn't find how to easily do that. Is it even possible?

推荐答案

在Jest中你必须将一个函数传递给expect（function）.toThrow（空格或类型错误）。

In Jest you have to pass a function into expect(function).toThrow(blank or type of error).

示例：

test("Test description", () => {
  const t = () => {
    throw new TypeError();
  };
  expect(t).toThrow(TypeError);
});

如果你需要测试现有函数是否抛出一组参数，你必须换行它位于expect（）中的匿名函数内。

If you need to test an existing function whether it throws with a set of arguments, you have to wrap it inside an anonymous function in expect().

示例：

test("Test description", () => {
  expect(() => {http.get(yourUrl, yourCallbackFn)}).toThrow(TypeError);
});

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