Even though this is an old question, I would like to add a new thought to the discussion. I have extended the Arrange, Act, Assert pattern to be Expected, Arrange, Act, Assert. You can make an expected exception pointer, then assert it was assigned to. This feels cleaner than doing your Asserts in a catch block, leaving your Act section mostly just for the one line of code to call the method under test. You also don't have to Assert.Fail(); or return from multiple points in the code. Any other exception thrown will cause the test to fail, because it won't be caught, and if an exception of your expected type is thrown, but the it wasn't the one you were expecting, Asserting against the message or other properties of the exception help make sure your test won't pass inadvertently.

[TestMethod]
public void Bar_InvalidDependency_ThrowsInvalidOperationException()
{
    // Expectations
    InvalidOperationException expectedException = null;
    string expectedExceptionMessage = "Bar did something invalid.";

    // Arrange
    IDependency dependency = DependencyMocks.Create();
    Foo foo = new Foo(dependency);

    // Act
    try
    {
        foo.Bar();
    }
    catch (InvalidOperationException ex)
    {
        expectedException = ex;
    }

    // Assert
    Assert.IsNotNull(expectedException);
    Assert.AreEqual(expectedExceptionMessage, expectedException.Message);
}

您可以通过简单的一行代码来实现这一点。

如果你的foo.bar()操作是异步的:

await Assert.ThrowsExceptionAsync<Exception>(() => foo.bar());

如果foo.bar()不是异步的

Assert.ThrowsException<Exception>(() => foo.bar());

如果你正在使用MSTest，它最初没有ExpectedException属性，你可以这样做:

try 
{
    SomeExceptionThrowingMethod()
    Assert.Fail("no exception thrown");
}
catch (Exception ex)
{
    Assert.IsTrue(ex is SpecificExceptionType);
}

如果你使用NUNIT，你可以这样做:

Assert.Throws<ExpectedException>(() => methodToTest());

也可以存储抛出的异常以便进一步验证:

ExpectedException ex = Assert.Throws<ExpectedException>(() => methodToTest());
Assert.AreEqual( "Expected message text.", ex.Message );
Assert.AreEqual( 5, ex.SomeNumber);

参见:http://nunit.org/docs/2.5/exceptionAsserts.html

这适用于Visual Studio Team Test(又名MSTest) 在处理数据库或http事务时。系统应该在某处抛出异常，使用Assert.ThrowExceptionAsync<>()将捕获您的throw事件。(在这些情况下，Assert.ThrowException<>()不会捕获异常)。

   [TestMethod]
   public void Invalid_Input_UserName_Should_Throw_Exception()
   {
       await Assert.ThrowExceptionAsync<ExpectedExceptionType>(()=> new LogonInfo(InvalidInputInUserNameFormat,"P@ssword"));
   }

在我正在做的一个项目中，我们有另一个解决方案。

首先，我不喜欢ExpectedExceptionAttribute，因为它确实考虑了导致异常的方法调用。

我用一个helper方法来代替它。

Test

[TestMethod]
public void AccountRepository_ThrowsExceptionIfFileisCorrupt()
{
     var file = File.Create("Accounts.bin");
     file.WriteByte(1);
     file.Close();

     IAccountRepository repo = new FileAccountRepository();
     TestHelpers.AssertThrows<SerializationException>(()=>repo.GetAll());            
}

HelperMethod

public static TException AssertThrows<TException>(Action action) where TException : Exception
    {
        try
        {
            action();
        }
        catch (TException ex)
        {
            return ex;
        }
        Assert.Fail("Expected exception was not thrown");

        return null;
    }

很整洁，不是吗?)