xunit test Fact multiple times

问题

I have some methods that rely on some random calculations to make a suggestion and I need to run the Fact several times to make sure is ok.

I could include a for loop inside the fact i want to test but because there are several test where I want to do this I was lookup for a cleaner approach, something like this Repeat attribute in junit: http://www.codeaffine.com/2013/04/10/running-junit-tests-repeatedly-without-loops/

Can I easily implement something like this in xunit?

回答1:

You'll have to create a new DataAttribute to tell xunit to run the same test multiple times.

Here's is a sample following the same idea of junit:

public class RepeatAttribute : DataAttribute
{
    private readonly int _count;

    public RepeatAttribute(int count)
    {
        if (count < 1)
        {
            throw new ArgumentOutOfRangeException(nameof(count), 
                  "Repeat count must be greater than 0.");
        }
        _count = count;
    }

    public override IEnumerable<object[]> GetData(MethodInfo testMethod)
    {
        return Enumerable.Repeat(new object[0], _count);
    }
}

With this code in place, you just need to change your Fact to Theory and use the Repeat like this:

[Theory]
[Repeat(10)]
public void MyTest()
{
    ...
}

回答2:

Had the same requirement but the accepted answers code was not repeating the tests so I have adapted it to:

public sealed class RepeatAttribute : Xunit.Sdk.DataAttribute
{
    private readonly int count;

    public RepeatAttribute(int count)
    {
        if (count < 1)
        {
            throw new System.ArgumentOutOfRangeException(
                paramName: nameof(count),
                message: "Repeat count must be greater than 0."
                );
        }
        this.count = count;
    }

    public override System.Collections.Generic.IEnumerable<object[]> GetData(System.Reflection.MethodInfo testMethod)
    {
        foreach (var iterationNumber in Enumerable.Range(start: 1, count: this.count))
        {
            yield return new object[] { iterationNumber };
        }
    }
}

While on the previous example the Enumerable.Repeat was being used it would only run the test 1 time, somehow xUnit is not repeating the test. Probably something they have changed a while ago. By changing to a foreach loop we are able to repeat each test but we also provide the "iteration number". When using it on the test function you have to add a parameter to your test function and decorate it as a Theory as shown here:

[Theory(DisplayName = "It should work")]
[Repeat(10)]
public void It_should_work(int iterationNumber)
{
...
}

This works for xUnit 2.4.0.

I've created a NuGet package to use this in case anyone is interested.

来源：https://stackoverflow.com/questions/31873778/xunit-test-fact-multiple-times

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