单元测试控制器中抛出的异常

Question

我目前正在单元测试，发送无效表单集合数据时发生错误。

唯一的例外是HttpPost指数ActionResult的方法（如下所示）中抛出：

[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) + "]"); 
     } 
    } 

到目前为止，我已经写了一个测试，成功击中异常（我已经启用代码覆盖率，我已经验证这一点正在使用，看看每个单独的测试正在执行什么代码），但目前测试失败，因为我还没有定义一种测试方法，已抛出异常，此测试的代码可以在下面找到：

[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); 
    } 

我看过使用[ExpectedException(typeof(Exception)]注释可以在这种情况下使用？

Answer 1

我冒昧地改变你的测试代码，稍微符合rhino-mocks的最新功能。它不再需要创建MockRepository，您可以使用静态类MockRepository并致电GenerateMock<>。我还将您的SuT（系统在测试中）实例化为以下的您的嘲笑规范。 （我对Nunit的使用经验比使用MSTest更好，主要是因为Nunit的发布频率更高，功能更可靠，再次，不确定它是否适用于TFS，但不应该很难找到）。

[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几乎相同的处理，除了你需要定义预期的异常多一点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"); 
} 

如果你有这部分的工作，你可以通过提供的链接重构它更好的可重用性。

Answer 2

测试这个最简单的方法是将调用包装在try-catch中并在catch块执行时设置布尔变量。例如：

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