Serial Prallel mixed tests

UnitTest.cs

using System;
using System.Threading.Tasks;
using Xunit;

namespace SerialAndParallelSpike
{
    [CollectionDefinition("Non-Parallel Collection", DisableParallelization = true)]
    public class NonParallelCollectionDefinitionClass
    {
    }

    [Collection("Non-Parallel Collection")]
    public class SerialTest
    {
        [Fact]
        public async Task Test10()
        {
            await Task.Delay(TimeSpan.FromSeconds(5));
            Assert.True(true);
        }
        [Fact]
        public async Task Test11()
        {
            await Task.Delay(TimeSpan.FromSeconds(5));
            Assert.True(true);
        }
    }

    public class ParallelTest01
    {
        [Fact]
        public async Task Test1()
        {
            await Task.Delay(TimeSpan.FromSeconds(5));
            Assert.True(true);
        }

        [Fact]
        public async Task Test2()
        {
            await Task.Delay(TimeSpan.FromSeconds(5));
            Assert.True(true);
        }
    }

    public class ParallelTest02
    {
        [Fact]
        public async Task Test3()
        {
            await Task.Delay(TimeSpan.FromSeconds(5));
            Assert.True(true);
        }

        [Fact]
        public async Task Test4()
        {
            await Task.Delay(TimeSpan.FromSeconds(5));
            Assert.True(true);
        }
    }


    public class TrulyParallelTest01
    {
        [Fact]
        public async Task Test5()
        {
            await Task.Delay(TimeSpan.FromSeconds(5));
            Assert.True(true);
        }

    }

    public class TrulyParallelTest02
    {
        [Fact]
        public async Task Test6()
        {
            await Task.Delay(TimeSpan.FromSeconds(5));
            Assert.True(true);
        }

    }
    [Collection("Serial")]
    public class SerialTest01
    {
        [Fact]
        public async Task Test7()
        {
            await Task.Delay(TimeSpan.FromSeconds(5));
            Assert.True(true);
        }
    }
    [Collection("Serial")]
    public class SerialTest02
    {
        [Fact]
        public async Task Test8()
        {
            await Task.Delay(TimeSpan.FromSeconds(5));
            Assert.True(true);
        }
    }
}