Question

上下文：

const Constructor = Vue.extend(MyComponent);
function createComponent() {
    vm = new Constructor({
      props,
    }).$mount();

    return vm;
  }

问题： 在测试中，我发现

vm.$nextTick().then(() => {
 expect(result).to.equal(expectedResult);
})

和

vm.$nextTick().then(() => {
 expect(result).to.not.equal(expectedResult);
})

都过去了。如何摆脱这种情况？ aync是否会以某种方式等待真相的过去？

Answer 1

首先：仅仅因为您可以使用.not否定任何断言，但这并不意味着您应该这样做。拥有权利的同时也被赋予了重大的责任。通常最好断言一个预期的输出已经产生，而不是断言没有产生无数意外的输出之一。

Equal表示目标严格（===）等于给定的val。

expect(2).to.equal(2); // Recommended
expect(2).to.not.equal(1); // Not recommended

好吧，现在，根据您的情况，您可能希望在链的前面添加.deep，以使用深度相等代替：

// Target object deeply (but not strictly) equals `{a: 1}`
expect({a: 1}).to.deep.equal({a: 1});
expect({a: 1}).to.not.equal({a: 1});

// Target array deeply (but not strictly) equals `[1, 2]`
expect([1, 2]).to.deep.equal([1, 2]);
expect([1, 2]).to.not.equal([1, 2]);

解释为什么很容易：

1 === 1 // These are primitives, they hold the same reference - they are strictly equal
1 == '1' // These are two different primitives, through type coercion they hold the same value - they are loosely equal
{ a: 1 } !== { a: 1 } // These are two different objects, they hold different references and so are not strictly equal - even though they hold the same values inside
{ a: 1 } != { a: 1 } // They have the same type, meaning loose equality performs the same check as strict equality - they are still not equal.

猜“ to.equal”使用“ deep-eql”算法=> package。

var deepEql = require("deep-eql");
deepEql({ a: 1 }, { a: 1 }) === true // deepEql can determine that they share the same keys and those keys share the same values, therefore they are deeply equal!

您想进一步了解chai方法吗？他们的docs很棒。

vue.nextTick误报

1 个答案: