我想测试一个异步组件方法,我想我正确地使用了Angular 4的异步测试功能,但它不工作。我的问题是,当我运行测试时,不等待供Promise解决。看起来,函数的异步特性导致超时被触发,并且测试过早退出。无论如何,测试都会通过,因为whenStable()
中的所有expect()
语句都会被跳过。为什么我的异步Angular Jasmine单元测试不工作?
如果我省略了async()
包装功能和开关传递一个done
回调,并在whenStable()
块的末尾调用它的茉莉花语法,它工作正常。谁能告诉我为什么它不适用于Angular async()
包装?
我的代码如下所示:
// my.component.ts
ngOnInit() {
this.getResults().then((results) => {
this.results = results;
});
}
// My asynchronous function, which takes 1.5s to load results
getResults() {
let promise = new Promise((resolve) => {
setTimeout(() => {
resolve('foo');
}, 1500);
})
return promise;
}
// my.component.spec.ts (Angular async version which doesn't work)
it('should load results', async(() => {
spyOn(component, 'getResults').and.returnValue(Promise.resolve('bar'));
component.ngOnInit();
fixture.whenStable().then(() => {
// Everything in here gets skipped when I run the test
fixture.detectChanges();
// This should cause the test to fail, but it doesn't because it's not run in time
expect(true).toBe(false)
});
}));
// my.component.spec.ts (Jasmine version that works)
it('should load results', (done) => {
spyOn(component, 'getResults').and.returnValue(Promise.resolve('bar'));
component.ngOnInit();
fixture.whenStable().then(() => {
fixture.detectChanges();
// This should fail and it does because the test works using Jasmine's "done" callback
expect(true).toBe(false);
done();
});
});
尝试调用'夹具。 detectChanges();'而不是'component.ngOnInit();'它也会运行'ngOnInit()',因为这是你第一次调用它。 –
这里有什么问题? https://plnkr.co/edit/MIDy85L9fVOtdvyXKnuS?p=preview你'getResult()'方法不会被执行,因为你嘲笑它 – yurzui
@AmitChigadani谢谢,但这并不行。 '期望(true).toBe(false)'仍然通过。 – Stewart