單元測試控制器中拋出的異常

Question

我目前正在單元測試，發送無效表單集合數據時發生錯誤。

唯一的例外是HttpPost指數ActionResult的方法（如下所示）中拋出：

[HttpPost] 
    [ValidateAntiForgeryToken] 
    public ActionResult Index(FormCollection formCollection, PaymentType payType, string progCode) 
    { 
     ActionResult ar = redirectFromButtonData(formCollection, payType, progCode); 

     if (ar != null) 
     { 
      return ar; 
     } 
     else 
     { 
      throw new Exception("Cannot redirect to payment form from cohort decision - Type:[" + payType.ToString() + "] Prog:[" + Microsoft.Security.Application.Encoder.HtmlEncode(progCode) + "]"); 
     } 
    } 

到目前爲止，我已經寫了一個測試，成功擊中異常（我已經啓用代碼覆蓋率，我已經驗證這一點正在使用，看看每個單獨的測試正在執行什麼代碼），但目前測試失敗，因爲我還沒有定義一種測試方法，已拋出異常，此測試的代碼可以在下面找到：

[TestMethod] 
    public void Error_Is_Thrown_If_HVM_FormCollection_Data_Is_Incorrect() 
    { 
     var formCollection = new FormCollection(); 
     formCollection.Add("__RequestVerificationToken", "__RequestVerificationToken"); 
     formCollection.Add("invalid - invalid", "invalid- invalid"); 


     var payType = new PaymentType(); 
     payType = PaymentType.deposit; 

     var progCode = "hvm"; 

     var mocks = new MockRepository(); 

     var httpRequest = mocks.DynamicMock<HttpRequestBase>(); 
     var httpContext = mocks.DynamicMock<HttpContextBase>(); 
     controller.ControllerContext = new ControllerContext(httpContext, new RouteData(), controller); 
     mocks.ReplayAll(); 

     httpRequest.Expect(r => r.Url).Return(new Uri("http://localhost:8080/hvm/full/self/")).Repeat.Any(); 

     httpContext.Expect(c => c.Request).Return(httpRequest).Repeat.Any(); 

     var result = controller.Index(formCollection, payType, progCode); 
    } 

我看過使用[ExpectedException(typeof(Exception)]註釋可以在這種情況下使用？

Answer 1

我冒昧地改變你的測試代碼，稍微符合rhino-mocks的最新功能。它不再需要創建MockRepository，您可以使用靜態類MockRepository並致電GenerateMock<>。我還將您的SuT（系統在測試中）實例化爲以下的您的嘲笑規範。 （我對Nunit的使用經驗比使用MSTest更好，主要是因爲Nunit的發佈頻率更高，功能更可靠，再次，不確定它是否適用於TFS，但不應該很難找到）。

[Test] // Nunit 
[ExpectedException(typeof(Exception)) // NOTE: it's wise to throw specific 
// exceptions so that you prevent false-positives! (another "exception" 
// might make the test pass while it's a completely different scenario) 
public void Error_Is_Thrown_If_HVM_FormCollection_Data_Is_Incorrect() 
{ 
    var formCollection = new FormCollection(); 
    formCollection.Add("__RequestVerificationToken", "__RequestVerificationToken"); 
    formCollection.Add("invalid - invalid", "invalid- invalid"); 

    var payType = new PaymentType(); 
    payType = PaymentType.deposit; 

    var progCode = "hvm"; 

    var httpRequest = MockRepository.GenerateMock<HttpRequestBase>(); 
    var httpContext = MockRepository.GenerateMock<HttpContextBase>(); 

    // define behaviour 
    httpRequest.Expect(r => r.Url).Return(new Uri("http://localhost:8080/hvm/full/self/")).Repeat.Any(); 
    httpContext.Expect(c => c.Request).Return(httpRequest).Repeat.Any(); 

    // instantiate SuT (system under test) 
    controller.ControllerContext = new ControllerContext(httpContext, new RouteData(), controller); 

    // Test the stuff, and if nothing is thrown then the test fails 
    var result = controller.Index(formCollection, payType, progCode); 
} 

和MStest幾乎相同的處理，除了你需要定義預期的異常多一點oldskool。 Assert exception from NUnit to MS TEST：

[TestMethod] // MStest 
public void Error_Is_Thrown_If_HVM_FormCollection_Data_Is_Incorrect() 
{ 
    try 
    { 
     var formCollection = new FormCollection(); 
     formCollection.Add("__RequestVerificationToken", "__RequestVerificationToken"); 
     formCollection.Add("invalid - invalid", "invalid- invalid"); 

     var payType = new PaymentType(); 
     payType = PaymentType.deposit; 

     var progCode = "hvm"; 

     var httpRequest = MockRepository.GenerateMock<HttpRequestBase>(); 
     var httpContext = MockRepository.GenerateMock<HttpContextBase>(); 

     // define behaviour 
     httpRequest.Expect(r => r.Url).Return(new Uri("http://localhost:8080/hvm/full/self/")).Repeat.Any(); 
     httpContext.Expect(c => c.Request).Return(httpRequest).Repeat.Any(); 

     // instantiate SuT (system under test) 
     controller.ControllerContext = new ControllerContext(httpContext, new RouteData(), controller); 

     // Test the stuff, and if nothing is thrown then the test fails 
     var result = controller.Index(formCollection, payType, progCode); 
    } 
    catch (Exception) 
    { 
     Assert.Pass(); 
    } 
    Assert.Fail("Expected exception Exception, was not thrown"); 
} 

如果你有這部分的工作，你可以通過提供的鏈接重構它更好的可重用性。

Answer 2

測試這個最簡單的方法是將調用包裝在try-catch中並在catch塊執行時設置布爾變量。例如：

var exceptionIsThrown = false; 
ActionResult result; 
try 
{ 
    result = controller.Index(formCollection, payType, progCode); 
} 
catch(Exception) 
{ 
    exceptionIsThrown = true; 
}