xUnit1049 Error

Do not use 'async void' for test methods as it is no longer supported

Cause

A violation of this rule occurs when an async test method returns void.

Support for async void test methods has been removed in xUnit.net v3. This rule will only trigger for v3 projects.

To fix a violation of this rule, change the test method return type to Task or ValueTask.

using Xunit;

public class TestClass
{
    [Fact]
    public async void TestMethod()
    {
        // ...
    }
}

using System.Threading.Tasks;
using Xunit;

public class TestClass
{
    [Fact]
    public async Task TestMethod()
    {
        // ...
    }
}

using System.Threading.Tasks;
using Xunit;

public class TestClass
{
    [Fact]
    public async ValueTask TestMethod()
    {
        // ...
    }
}