如何在 NUnit 测试/Selenium/C# 中将意外异常转换为断言失败？

Question

I am a newbie and couldn't make out in the NUnit documentation. I think this link contains useful information: https://docs.nunit.org/articles/nunit/writing-tests/constraints/ThrowsConstraint.html

How to convert unexpected exception whether "element is not clickable", "click is intersepted" into an assertion failure.

Without a convert, the [Retry] NUnit attribute does not restart failed tests on an unexpected exception.

test suite structure

    [SetUp]
    public void Setup()
    {
        driver = new OpenQA.Selenium.Chrome.ChromeDriver();
        driver.Manage().Window.Maximize();
    }

    ....

    [Test]
    [Retry(3)]
    public void voidName()
    {
       Assert.That(() =>
            {
                 var name = new className(driver);
                 name.methodName();
            }, 
            Throws.Nothing);
       
    }
    .....

    [TearDown]
    public void TearDown()
    {
            driver.Quit();
    }

    

test method structure

public void methodName()
        {
            ....
            ....
          if(result == true)
           {
              Assert.Pass();
           }
          else
           {
              Assert.Fail();
           }
       


        }

Regardless of whether Pass or Fail has a methodName, voidName returns failed

Answer 1

Edit # 2:

In NUnit (or any unit testing framework) if a unit test passes any assertions, the program continues from that point normally. If it fails an Assertion, the entire unit test fails at that point.

So it seems that you need to debug your code as it is not working as you expect. Your unit test is failing because it is encountering the Assert.Fail() in your logic.

That being said, I don't think you should place your Assertions within the logic of your code. Instead, you should throw exceptions, and keep Assert statements only in your unit tests . Otherwise, such issues will be difficult to avoid.

public void methodName()
{
    ....
    ....
    if(result == true)
    { 
        // No need to call assert statements here
    }
    else
    {
        throw new System.Exception("Write your custom error message here.");
    }
    ....
}

Edit # 1:

Okay, now that you have shared your code, You can do as shown as Charlie mentioned

[Test] 
[Retry(3)] 
public void DepositFoOpen() 
{
    Assert.That(
        () => 
        { 
            var MMFO = new MMFO_Tests_Lib.DepositFO(driver);
            MMFO.DepositFoOpen();
        }, Throws.Nothing); 
}

or if you want to use try-catch block as I mentioned:

[Test] 
[Retry(3)] 
public void DepositFoOpen() 
{
    try
    {
        var MMFO = new MMFO_Tests_Lib.DepositFO(driver);
        MMFO.DepositFoOpen();
    }
    catch(Exception ex)
    {
        Assert.Fail();
    }
}

Answer 2

In this case, you want the ThrowsNothingConstraint

Assert.That(() => SomeMethod(), Throws.Nothing);

UPDATE: I'd give you more detail if your question had details. :-)

All I know from your question is that some method of yours causes an exception to be thrown. I called that method "SomeMethod" 'cause that's all I know. I wrapped it in an Assert so that the error would be for the specific line of code, which causes the exception.

If you don't know which method call causes the exception, then you should figure it out. Most likely, it's some call you make to Selenium.