BepInEx/BepInExTests/AssemblyInit.cs

using System.IO;
using Microsoft.VisualStudio.TestTools.UnitTesting;

namespace BepInEx.Tests
{
    [TestClass]
    public class AssemblyInit
    {
        private static string _testPath;

        [AssemblyInitialize]
        public static void InitAss(TestContext context)
        {
            _testPath = Path.Combine(Path.GetTempPath(), "BepinexTestDir");
            Directory.CreateDirectory(_testPath);

            var exePath = Path.Combine(_testPath, "Text.exe");
            File.WriteAllBytes(exePath, new byte[] { });

            Paths.SetExecutablePath(_testPath);
        }

        [AssemblyCleanup]
        public static void CleanupAss() => Directory.Delete(_testPath, true);
    }
}