小编典典

Mocha/Chai expect.to.throw不捕捉投掷错误

javascript

我在让Chai的expect.to.thrownode.js应用程序进行测试时遇到问题。测试会不断导致抛出的错误,但是如果我将测试用例包装在try和catch中并断言所捕获的错误,它将起作用。

难道expect.to.throw不喜欢的工作,我认为它应该还是什么?

it('should throw an error if you try to get an undefined property', function (done) {
  var params = { a: 'test', b: 'test', c: 'test' };
  var model = new TestModel(MOCK_REQUEST, params);

  // neither of these work
  expect(model.get('z')).to.throw('Property does not exist in model schema.');
  expect(model.get('z')).to.throw(new Error('Property does not exist in model schema.'));

  // this works
  try { 
    model.get('z'); 
  }
  catch(err) {
    expect(err).to.eql(new Error('Property does not exist in model schema.'));
  }

  done();
});

失败:

19 passing (25ms)
  1 failing

  1) Model Base should throw an error if you try to get an undefined property:
     Error: Property does not exist in model schema.

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2020-04-25

共1个答案

小编典典

您必须将一个函数传递给expect。像这样:

expect(model.get.bind(model, 'z')).to.throw('Property does not exist in model schema.');
expect(model.get.bind(model, 'z')).to.throw(new Error('Property does not exist in model schema.'));

执行此操作的方式将传递给callexpect的结果model.get('z')。但是要测试是否抛出了某些东西,您必须将一个函数传递给expect,该函数expect会自行调用。bind上面使用的方法创建了一个新函数,当调用该函数时,将model.get使用this设置为的值model和设置为的第一个参数进行调用'z'

2020-04-25