如何在Jest中测试抛出的异常的类型

本文介绍了如何在Jest中测试抛出的异常的类型的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我正在使用一些代码，在这些代码中，我需要测试函数抛出的异常的类型(是TypeError，ReferenceError等吗?).

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

我当前的测试框架是AVA，我可以将其作为第二个参数t.throws方法进行测试，如下所示:

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');
});

我开始用Jest重写测试，找不到如何轻松地做到这一点.甚至有可能吗?

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

推荐答案

在Jest中，您必须将函数传递到expect(function).toThrow(<blank or type of error>).

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);
});

或者如果您还想检查错误消息:

Or if you also want to check for error message:

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

如果需要测试现有函数是否带有一组参数，则必须将其包装在expect()中的匿名函数中.

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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