如何测试使用promise的AngularJS组件？

我想对以下组件进行单元测试

myApp.component('myComponent', {
  controller: function($q) {
    let serviceDummy = $q((resolve, reject) => resolve(42));
    this.number = 0;
    this.$onInit = () => {
      serviceDummy.then((res) => {this.number = res; });
      serviceDummy.then(console.log);
    }
  },
  template: '<p>The answer is {{$ctrl.number}}</p>'
});

该组件工作正常，但测试失败。 首先返回被测函数创建的承诺

this.$onInit = () => {
    //vvvv RETURN promise
    return serviceDummy.then((res) => {this.number = res; });
}

然后使用Jasmine提供的Then

done

函数作为

it

方法的测试处理程序的参数：

  it('should set the number to 42', function testHandler(done) {
    var p = controller.$onInit();
    p.then(function() {
      expect(controller.number).toBe(42);
      done();
    });
    _rootScope.$apply();
  });

在expect之前添加$rootScope.$digest（）

  it('should set the number to 42', function testHandler(done) {
    var p = controller.$onInit();
    p.then(function() {
      expect(controller.number).toBe(42);
      done();
    });
    _rootScope.$apply();
  });