在Karma上测试异步用户界面操作

Question

我在下面进行了以下测试，其中我更新一个文本字段，然后进行API调用，然后，根据API响应，我希望另一个文本字段具有相同的值。但是，它始终失败，并显示错误'------------------------------------- Function Do999(ByVal ThreeDigits) As String '------------------------------------- 'Spells numbers from 001 to 999 to Words 'Mohsen Alyafei 17 Oct 2018 'Modified to add "and" by Mohsen Alyfei 07 July 2019 'On Entry: ThreeDigits 3 digit number 001 to 999 'On Exit : String of number in English words '----------------------------------------- Dim Ones(), Tens(), Separator As String, h As String, t As String, N1 As Integer, N2 As Integer, annd As String Ones = Array("", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen") Tens = Array("", "", "Twenty", "Thirty", "Forty", "Fifty", "Sixty", "Seventy", "Eighty", "Ninety") ThreeDigits = Right("000" & ThreeDigits, 3) 'Align to 3 digits annd = " " 'added to add "and" If Right(ThreeDigits, 1) <> "0" Then Separator = "-" N1 = Left(ThreeDigits, 1): N2 = Right(ThreeDigits, 2) If N2 > 19 Then t = Tens(Val(Mid(ThreeDigits, 2, 1))) & Separator & Ones(Val(Right(ThreeDigits, 1))) Else t = Ones(N2) If N1 > 0 Then h = Ones(N1) & " Hundred" If N2 > 0 Then annd = " and " 'added to add "and" End If Do999 = Trim(h & annd & t) 'var "annd" is normally a space End Function ，根据API的响应，我期望结果为2 = 2。知道我该如何解决吗？

这里的堆叠闪电战：https://stackblitz.com/edit/http-get-post-dgcuur

测试

Expected '0' to equal '2'.

查看

it('should successfuly convert A to A', fakeAsync(() => {
      fixture.detectChanges();
      fixture.whenStable().then(() => {
        let fromAmountValueEl = fixture.debugElement.query(By.css('#fromAmountValue')).nativeElement;
        expect(fromAmountValueEl.value).toEqual('0');
        let toAmountValueEl = fixture.debugElement.query(By.css('#toAmountValue')).nativeElement;
        expect(toAmountValueEl.value).toEqual('0');
        fromAmountValueEl.value = '2'
        fromAmountValueEl.dispatchEvent(new Event('input'));
        fromAmountValueEl.dispatchEvent(new KeyboardEvent('keyup', {
          'key': 'Enter'
        }));
        tick();
        fixture.whenStable().then(() => {
          fixture.detectChanges();
          expect(fromAmountValueEl.value).toEqual('2');
          expect(toAmountValueEl.value).toEqual('2');
        });
      });
    }));

控制器

      <input class="form-control form-control-lg" type="number" placeholder="0" [(ngModel)]="fromAmount"
        (keyup)="updateRates()" id="fromAmountValue">
      <select class="form-control form-control-lg" id="fromCurrency">
        <option value="GBP">GBP</option>
      </select>

      <input class="form-control form-control-lg" type="number" placeholder="0" [(ngModel)]="toAmount"
        (keyup)="updateRates()" id="toAmountValue">
      <select class="form-control form-control-lg" [(ngModel)]="toCurrency" id="toCurrency">
        <option value="GBP">GBP</option>
      </select>