Argument Formatters

When writing data-driven tests, especially with custom classes as arguments, the test explorer may only show the class name, making it hard to distinguish test cases.
Argument formatters let you control how arguments are displayed in test names and test explorers.

If you want control over how injected arguments appear in the test explorer, you can create a class that inherits from ArgumentDisplayFormatter and then decorate your test with the [ArgumentDisplayFormatter<T>] attribute.

For example:

    [Test]
    [MethodDataSource(nameof(SomeMethod))]
    [ArgumentDisplayFormatter<SomeClassFormatter>]
    public async Task Test(SomeClass)
    {
        await Assert.That(TestContext.Current!.GetTestDisplayName()).IsEqualTo("A super important test!");
    }

public class MyFormatter : ArgumentDisplayFormatter
{
    public override bool CanHandle(object? value)
    {
        return value is SomeClass;
    }

    public override string FormatValue(object? value)
    {
        var someClass = (SomeClass)value;
        return $"One: {someClass.One} | Two: {someClass.Two}";
    }
}

info

You can apply multiple [ArgumentDisplayFormatter<T>] attributes if you have different types to format.
The first formatter whose CanHandle returns true will be used.