问题描述

我有一组测试用例，其中一些预计会引发异常.因此，我已将这些测试的属性设置为预期会出现如下异常:

I've got a set of test cases, some of which are expected to throw exceptions. Because of this, I have have set the attributes for these tests to expect exceptions like so:

[ExpectedException("System.NullReferenceException")]

当我在本地运行测试时，一切都很好.但是，当我将测试转移到运行 TeamCity 的 CI 服务器时，所有预期异常的测试都会失败.这是一个已知的错误.

When I run my tests locally all is good. However when I move my tests over to the CI server running TeamCity, all my tests that have expected exceptions fail. This is a known bug.

我知道 NUnit 还提供了 Assert.Throws<> 和 Assert.Throws 方法.

I am aware that there is also the Assert.Throws<> and Assert.Throws methods that NUnit offers.

我的问题是如何使用这些而不是我当前使用的属性?

My question is how can I make use of these instead of the attribute I'm currently using?

我查看了 StackOverflow 并尝试了一些似乎对我不起作用的方法.

I've had a look around StackOverflow and tried a few things none of which seem to work for me.

有没有简单的 1 行解决方案来使用它?

Is there a simple 1 line solution to using this?

推荐答案

我不确定你的尝试是否会给你带来麻烦，但你可以简单地将 lambda 作为第一个参数传递给 Assert.Throws.这是我通过的一项测试中的一项:

I'm not sure what you've tried that is giving you trouble, but you can simply pass in a lambda as the first argument to Assert.Throws. Here's one from one of my tests that passes:

Assert.Throws<ArgumentException>(() => pointStore.Store(new[] { firstPoint }));

<小时>

好的，这个例子可能有点冗长.假设我有一个测试

Okay, that example may have been a little verbose. Suppose I had a test

[Test]
[ExpectedException("System.NullReferenceException")]
public void TestFoo()
{
    MyObject o = null;
    o.Foo();
}

这会正常通过，因为 o.Foo() 会引发空引用异常.

which would pass normally because o.Foo() would raise a null reference exception.

然后您将删除 ExpectedException 属性并将您对 o.Foo() 的调用包装在 Assert.Throws 中.

You then would drop the ExpectedException attribute and wrap your call to o.Foo() in an Assert.Throws.

[Test]
public void TestFoo()
{
    MyObject o = null;
    Assert.Throws<NullReferenceException>(() => o.Foo());
}

Assert.Throws尝试调用以委托表示的代码片段，以验证它是否引发了特定异常."() =>DoSomething() 语法表示一个 lambda，本质上是一个匿名方法.所以在这种情况下，我们告诉 Assert.Throws 执行代码片段 o.Foo().

Assert.Throws "attempts to invoke a code snippet, represented as a delegate, in order to verify that it throws a particular exception." The () => DoSomething() syntax represents a lambda, essentially an anonymous method. So in this case, we are telling Assert.Throws to execute the snippet o.Foo().

所以不，你不能像添加属性那样只添加一行；您需要在对 Assert.Throws 的调用中显式包装将引发异常的测试部分.您不一定必须使用 lambda，但这通常是最方便的.

So no, you don't just add a single line like you do an attribute; you need to explicitly wrap the section of your test that will throw the exception, in a call to Assert.Throws. You don't necessarily have to use a lambda, but that's often the most convenient.

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