Custom display name for DynamicDataAttribute

[bstoney]

Description

Is it possible to add an option to the DynamicDataAttribute allowing similar functionality to the DataRowAttribute.DisplayName. This would allow tests with similar parameters to be given more meaningful names and therefore make it easier to determine which set of parameter is producing a particular result.

A possible solution would be to set the a DisplayName property to the name of a method, just as dynamicDataSourceName is currently, and match the method signature of the default GetDisplayName method. This will allow a custom display name to be generated depending on the parameter set.

Current Behaviour

With the test class:

[TestClass]
public class Tests
{
    [TestMethod]
    [DynamicData(nameof(Tests.TestMethodTests))]
    public void TestMethod(string param1, string param2)
    {
        Assert.IsNotNull(param1);
    }

    private static IEnumerable<object[]> TestMethodTests
    {
        get
        {
            yield return new object[] { "", null };
            yield return new object[] { null, "" };
        }
    }
}

Displays output where it is not clear which set of parameters caused the failure

Failed   TestMethod (,)
Error Message:
    Assert.IsNotNull failed.
Stack Trace:
    ...

Possible Solution

// ....
    [DynamicData(nameof(Tests.TestMethodTests), DisplayName = nameof(Tests.GetTestMethodDisplayName))]
// ...
    public static string GetTestMethodDisplayName(MethodInfo methodInfo, object[] data)
    {
        // ....
    }
// ....

Current Workaround

As a work around I have been adding an unused sting parameter to identify the test e.g:

// ....
    public void TestMethod(string testName, string param1, string param2)
// ....
        yield return new object[] { "Param2 null", "", null };
        yield return new object[] { "Param1 null", null, "" };
// ....

[cltshivash]

Brad Stoney (@bstoney) This is a fair suggestion and we would be more than happy to welcome contribution for this feature addition.

[jayaranigarg]

If we have a DisplayName property in DynamicData attribute, then each row of data would effectively have same base name i.e. GetTestMethodDisplayName, combined with data[] which be different. That is what happens in the normal workflow as well i.e. you have testmethod name combined with data[] for each row.

I think your ask is to have different base name for each row of data followed by data[]. Did I understand you correctly?

[bstoney]

Basically yes. Each row of data could have a different base name, though I was thinking that it would be up to the DisplayName implementation to add the data[] if necessary. I will add the feature and submit a PR for you to review.