引发错误，但Jest的`toThrow()`不能捕获错误

本文介绍了引发错误，但Jest的`toThrow()`不能捕获错误的处理方法，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

这是我的错误代码:

 FAIL  build/__test__/FuncOps.CheckFunctionExistenceByString.test.js
  ●
    expect(CheckFunctionExistenceByStr(
      'any string', 'FunctionThatDoesNotExistsInString'
    )).toThrow();


    Function FunctionThatDoesNotExistsInString does not exists in string.

      at CheckFunctionExistenceByStr (build/FuncOps.js:35:15)
      at Object.<anonymous> (build/__test__/FuncOps.CheckFunctionExistenceByString.test.js:12:51)
          at new Promise (<anonymous>)
          at <anonymous>

您可以看到错误确实发生了:函数FunctionThatThatDoesNotExistsInString在字符串中不存在..但是，在Jest中并没有将其捕获为通行证.

As you can see the error did indeed occurred: Function FunctionThatDoesNotExistsInString does not exists in string.. However it is not captured as a pass in Jest.

这是我的代码:

test(`
    expect(CheckFunctionExistenceByStr(
      'any string', 'FunctionThatDoesNotExistsInString'
    )).toThrow();
  `, () => {
    expect(CheckFunctionExistenceByStr(
      'any string', 'FunctionThatDoesNotExistsInString'
    )).toThrow();
  }
);

推荐答案

expect(fn).toThrow()需要一个函数 fn ，该函数在调用时，引发异常.

expect(fn).toThrow() expects a function fn that, when called, throws an exception.

但是，您立即调用 CheckFunctionExistenceByStr ，这将导致函数在运行断言之前抛出.

However you are calling CheckFunctionExistenceByStr immediatelly, which causes the function to throw before running the assert.

替换

test(`
    expect(CheckFunctionExistenceByStr(
      'any string', 'FunctionThatDoesNotExistsInString'
    )).toThrow();
  `, () => {
    expect(CheckFunctionExistenceByStr(
      'any string', 'FunctionThatDoesNotExistsInString'
    )).toThrow();
  }
);

使用

test(`
    expect(() => {
      CheckFunctionExistenceByStr(
        'any string', 'FunctionThatDoesNotExistsInString'
      )
    }).toThrow();
  `, () => {
    expect(() => {
      CheckFunctionExistenceByStr(
        'any string', 'FunctionThatDoesNotExistsInString'
      )
    }).toThrow();
  }
);

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