如何使用ExpectedException属性强制执行异常消息

Question

我认为这两个测试的行为应该完全相同,事实上我已经使用MS Test在我的项目中编写了测试,现在却发现它不像NUnit那样尊重预期的消息.

NUnit(失败):

[Test, ExpectedException(typeof(System.FormatException), ExpectedMessage = "blah")]
public void Validate()
{
    int.Parse("dfd");
}

MS测试(通过):

[TestMethod, ExpectedException(typeof(System.FormatException), "blah")]
public void Validate()
{
    int.Parse("dfd");
}

无论我给ms测试什么消息,它都会通过.

如果消息不正确,有没有办法让ms测试失败？我甚至可以创建自己的异常属性吗？我宁愿不必为发生这种情况的每个测试编写一个try catch块.

Answer 1

我们在整个地方使用这个属性,我们明显误解了第二个参数(对我们感到羞耻).

但是,我们肯定用它来检查异常消息.以下是我们使用此页面提示的内容.它不处理全球化或继承的异常类型,但它可以满足我们的需求.同样,目标是简单地将RR'ExpectedException'与此类交换出来.(Bummer ExpectedException已被密封.)

public class ExpectedExceptionWithMessageAttribute : ExpectedExceptionBaseAttribute
{
    public Type ExceptionType { get; set; }

    public string ExpectedMessage { get; set; }

    public ExpectedExceptionWithMessageAttribute(Type exceptionType)
    {
        this.ExceptionType = exceptionType;
    }

    public ExpectedExceptionWithMessageAttribute(Type exceptionType, string expectedMessage)
    {
        this.ExceptionType = exceptionType;

        this.ExpectedMessage = expectedMessage;
    }

    protected override void Verify(Exception e)
    {
        if (e.GetType() != this.ExceptionType)
        {
            Assert.Fail(String.Format(
                            "ExpectedExceptionWithMessageAttribute failed. Expected exception type: {0}. Actual exception type: {1}. Exception message: {2}",
                            this.ExceptionType.FullName,
                            e.GetType().FullName,
                            e.Message
                            )
                        );
        }

        var actualMessage = e.Message.Trim();

        if (this.ExpectedMessage != null)
        {
            Assert.AreEqual(this.ExpectedMessage, actualMessage);
        }

        Console.Write("ExpectedExceptionWithMessageAttribute:" + e.Message);
    }
}

Answer 2

mstest第二个参数是测试失败时打印出来的消息.如果抛出formatexception,mstest将成功.我发现这篇文章可能有用

http://blogs.msdn.com/b/csell/archive/2006/01/13/expectedexception-might-not-be-what-you-ve-expected.aspx

Answer 3

@rcravens是正确的 - 第二个参数是在测试失败时打印的消息.我为解决这个问题所做的工作是我的测试方法略有不同.不可否认,我不喜欢这种方法,但它确实有效.

[TestMethod]
public void Validate()
{
    try
    {
        int.Parse("dfd");

        // Test fails if it makes it this far
        Assert.Fail("Expected exception was not thrown.");
    }
    catch (Exception ex)
    {
        Assert.AreEqual("blah", ex.Message);
    }
}

Answer 4

我通过添加对contains,case-insensitive和ResourcesType-ResourceName组合的支持,扩展了BlackjacketMack对我们项目的回答.

用法示例:

public class Foo
{
    public void Bar(string mode)
    {
        if (string.IsNullOrEmpty(mode)) throw new InvalidOperationException(Resources.InvalidModeSpecified);
    }

    public void Bar(int port)
    {
        if (port < 0 || port > Int16.MaxValue) throw new ArgumentOutOfRangeException("port");
    }
}

[TestClass]
class ExampleClass
{
    [TestMethod]
    [ExpectedExceptionWithMessage(typeof(InvalidOperationException), typeof(Samples.Resources), "InvalidModeSpecified")]
    public void Raise_Exception_With_Message_Resource()
    {
        new Foo().Bar(null);
    }

    [TestMethod]
    [ExpectedExceptionWithMessage(typeof(ArgumentOutOfRangeException), "port", true)]
    public void Raise_Exeception_Containing_String()
    {
        new Foo().Bar(-123);
    }
}

这是更新的课程:

public class ExpectedExceptionWithMessageAttribute : ExpectedExceptionBaseAttribute
{
    public Type ExceptionType { get; set; }

    public Type ResourcesType { get; set; }

    public string ResourceName { get; set; }

    public string ExpectedMessage { get; set; }

    public bool Containing { get; set; }

    public bool IgnoreCase { get; set; }

    public ExpectedExceptionWithMessageAttribute(Type exceptionType)
        : this(exceptionType, null)
    {
    }

    public ExpectedExceptionWithMessageAttribute(Type exceptionType, string expectedMessage)
        : this(exceptionType, expectedMessage, false)
    {
    }

    public ExpectedExceptionWithMessageAttribute(Type exceptionType, string expectedMessage, bool containing)
    {
        this.ExceptionType = exceptionType;
        this.ExpectedMessage = expectedMessage;
        this.Containing = containing;
    }

    public ExpectedExceptionWithMessageAttribute(Type exceptionType, Type resourcesType, string resourceName)
        : this(exceptionType, resourcesType, resourceName, false)
    {
    }

    public ExpectedExceptionWithMessageAttribute(Type exceptionType, Type resourcesType, string resourceName, bool containing)
    {
        this.ExceptionType = exceptionType;
        this.ExpectedMessage = ExpectedMessage;
        this.ResourcesType = resourcesType;
        this.ResourceName = resourceName;
        this.Containing = containing;
    }

    protected override void Verify(Exception e)
    {
        if (e.GetType() != this.ExceptionType)
        {
            Assert.Fail(String.Format(
                            "ExpectedExceptionWithMessageAttribute failed. Expected exception type: <{0}>. Actual exception type: <{1}>. Exception message: <{2}>",
                            this.ExceptionType.FullName,
                            e.GetType().FullName,
                            e.Message
                            )
                        );
        }

        var actualMessage = e.Message.Trim();

        var expectedMessage = this.ExpectedMessage;

        if (expectedMessage == null)
        {
            if (this.ResourcesType != null && this.ResourceName != null)
            {
                PropertyInfo resourceProperty = this.ResourcesType.GetProperty(this.ResourceName, BindingFlags.Static | BindingFlags.NonPublic | BindingFlags.Public);
                if (resourceProperty != null)
                {
                    string resourceValue = null;

                    try
                    {
                        resourceValue = resourceProperty.GetMethod.Invoke(null, null) as string;
                    }
                    finally
                    {
                        if (resourceValue != null)
                        {
                            expectedMessage = resourceValue;
                        }
                        else
                        {
                            Assert.Fail("ExpectedExceptionWithMessageAttribute failed. Could not get resource value. ResourceName: <{0}> ResourcesType<{1}>.",
                            this.ResourceName,
                            this.ResourcesType.FullName);
                        }
                    }
                }
                else
                {
                    Assert.Fail("ExpectedExceptionWithMessageAttribute failed. Could not find static resource property on resources type. ResourceName: <{0}> ResourcesType<{1}>.",
                        this.ResourceName,
                        this.ResourcesType.FullName);
                }
            }
            else
            {
                Assert.Fail("ExpectedExceptionWithMessageAttribute failed. Both ResourcesType and ResourceName must be specified.");
            }
        }

        if (expectedMessage != null)
        {
            StringComparison stringComparison = this.IgnoreCase ? StringComparison.OrdinalIgnoreCase : StringComparison.Ordinal;
            if (this.Containing)
            {
                if (actualMessage == null || actualMessage.IndexOf(expectedMessage, stringComparison) == -1)
                {
                    Assert.Fail(String.Format(
                                    "ExpectedExceptionWithMessageAttribute failed. Expected message: <{0}>. Actual message: <{1}>. Exception type: <{2}>",
                                    expectedMessage,
                                    e.Message,
                                    e.GetType().FullName
                                    )
                                );
                }
            }
            else
            {
                if (!string.Equals(expectedMessage, actualMessage, stringComparison))
                {
                    Assert.Fail(String.Format(
                                    "ExpectedExceptionWithMessageAttribute failed. Expected message to contain: <{0}>. Actual message: <{1}>. Exception type: <{2}>",
                                    expectedMessage,
                                    e.Message,
                                    e.GetType().FullName
                                    )
                                );
                }
            }
        }
    }
}