问题描述
在模板组件中,我正在使用@Watch
进行以下验证
@Watch('name')
validateName(newValue: string) {
const isBlank = typeof newValue !== 'string' || newValue === '';
console.log('AYE!',isBlank);
if (isBlank) { throw new Error('name: required') };
}
现在我要开玩笑地测试一下
it('throws error when name is not supplied',async () => {
const { root } = await newSpecPage({ components: [MyComponent],html: '<my-component></my-component>' });
expect(() => {
root.name = '';
}).toThrow(new Error('name: required'))
})
我得到的结果如下
expect(received).toThrow(expected)
Expected message: "name: required"
Received function did not throw
47 | expect(() => {
48 | root.name = '';
> 49 | }).toThrow(new Error('name: required'))
| ^
50 | })
51 | });
52 |
console.log
AYE! true
at MyComponent.validateName (src/xxx/my-component.tsx:31:13)
at Array.map (<anonymous>)
我想知道如何捕捉validateName
引发的错误?
解决方法
更改道具后,您必须使用异步waitForChanges()
。您可以通过调用然后使用rejects.toEqual(...)
来检查是否抛出。另外,您还必须返回expect(...)
语句,否则您的测试将在异步代码完成之前通过(并且您的控制台中将获得UnhandledPromiseRejectionWarning
)。
it('throws error when name is not supplied',async () => {
const { root,waitForChanges } = await newSpecPage({
components: [MyComponent],html: '<my-component></my-component>'
});
root.name = '';
return expect(waitForChanges()).rejects.toEqual(new Error('name: required'));
})
,
除了使用toThrow
,我们还可以通过try catch块实现类似的结果,如下所示。
模板还提供waitForChanges
方法,该方法使我们可以更改属性值并等待其生效
it('throws error when name is not supplied',async () => {
try {
const { root,waitForChanges } = await newSpecPage({ components: [MyComponent],html: `<my-component name="xxx"></my-component>` });
root.name = '';
await waitForChanges()
} catch (e) {
expect(e).toStrictEqual(Error('name: required'));
}
})