在VS内置单元测试中，如果你只是想验证抛出了“任何异常”，但你不知道类型，你可以使用catch all:

[TestMethod]
[ExpectedException(typeof(Exception), AllowDerivedTypes = true)]
public void ThrowExceptionTest()
{
    //...
}

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

有一个很棒的库叫做NFluent，它可以加速和简化你编写断言的方式。

编写抛出异常的断言非常简单:

    [Test]
    public void given_when_then()
    {
        Check.ThatCode(() => MethodToTest())
            .Throws<Exception>()
            .WithMessage("Process has been failed");
    }

作为一种替代方法，您可以尝试测试异常实际上是在您的测试中的下两行中抛出的。

var testDelegate = () => MyService.Method(params);
Assert.Throws<Exception>(testDelegate);

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);
}