如何在另一个类引发的测试类中捕获异常？

Question

I have a window form with one button and I am trying to test it with codedUitest. I want the test to fail if any exception is thrown but in the test class it doesn't catch the exception.

Here is my code:

public void button1_Click(object sender, EventArgs e)
{ 
    double[] dummy = new double[1];
    int i = 1;

    if (i > 0)
    {
        throw new System.IndexOutOfRangeException("index parameter is out of range.");      
    }
    else
    {             
        dummy[i] = 6;  
    }
}

The test method is:

public void CodedUITestMethod1()
{
    try
    {
        this.UIMap.TryBtn1();
    }
    catch (IndexOutOfRangeException)
    {
        Assert.Fail();
    }
}

Answer 1

You've written an integration test.

Disclaimer: I'm a web dev - so I have to assume this is similar to using a browser driver like selenium.

So what you're doing is telling a UI driver to click the button . This runs the code but it doesn't run it in the test context . Your test only has access to the UI.

In order to detect whether or not the error has been thrown, I guess you'll have to inspect the UI to see if a popup has appeared.

If you want to test just the method (which might be preferable depending on your situation) you can use NUnit and Moq.

using System;
using Moq;
using NUnit.Framework;

namespace Tests
{
    [TestFixture]
    class Tests
    {
        [Test]
        public void Throws()
        {
            var sender = new Mock<object>();
            var args = new Mock<EventArgs>();

            Assert.Throws<IndexOutOfRangeException>(() => button1_Click(sender.Object, args.Object));
        }

        public void button1_Click(object sender, EventArgs e)
        {
            double[] dummy = new double[1];
            int i = 1;

            if (i > 0)
            {

                throw new System.IndexOutOfRangeException("index parameter is out of range.");
            }
            else
            {
                dummy[i] = 6;
            }

        }
    }
}

Answer 2

You can add [ExpectedException(typeof(IndexOutOfRangeException))] attribute to your TestMethod. Have a look at MSTest Exception Handling .