diff --git a/tests/Tgstation.Server.Host.Tests/IO/TestPostWriteHandler.cs b/tests/Tgstation.Server.Host.Tests/IO/TestPostWriteHandler.cs
new file mode 100644
index 0000000000..7dd1ce45f2
--- /dev/null
+++ b/tests/Tgstation.Server.Host.Tests/IO/TestPostWriteHandler.cs
@@ -0,0 +1,85 @@
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Mono.Unix;
+using System;
+using System.Diagnostics;
+using System.IO;
+using System.Runtime.InteropServices;
+using System.Text;
+
+namespace Tgstation.Server.Host.IO.Tests
+{
+	[TestClass]
+	public sealed class TestPostWriteHandler
+	{
+		[TestMethod]
+		public void TestThrowsWithNullArg()
+		{
+			IPostWriteHandler postWriteHandler;
+			var isWindows = RuntimeInformation.IsOSPlatform(OSPlatform.Windows);
+			if (isWindows)
+				postWriteHandler = new WindowsPostWriteHandler();
+			else
+				postWriteHandler = new PosixPostWriteHandler();
+
+			Assert.ThrowsException<ArgumentNullException>(() => postWriteHandler.HandleWrite(null));
+		}
+
+		[TestMethod]
+		public void TestPostWrite()
+		{
+			IPostWriteHandler postWriteHandler;
+			var isWindows = RuntimeInformation.IsOSPlatform(OSPlatform.Windows);
+			if (isWindows)
+				postWriteHandler = new WindowsPostWriteHandler();
+			else
+				postWriteHandler = new PosixPostWriteHandler();
+
+			//test on a valid file first
+			var tmpFile = Path.GetTempFileName();
+			try
+			{
+				postWriteHandler.HandleWrite(tmpFile);
+
+				if (isWindows)
+					return; //you do nothing
+
+				//ensure it is now executable
+				File.WriteAllBytes(tmpFile, Encoding.UTF8.GetBytes("#!/bin/sh\n"));
+
+				using (var process = Process.Start(tmpFile))
+				{
+					process.WaitForExit();
+					Assert.AreEqual(0, process.ExitCode);
+				}
+
+				//run it again for the code coverage on that part where no changes are made if it's already executable
+				postWriteHandler.HandleWrite(tmpFile);
+			}
+			finally
+			{
+				File.Delete(tmpFile);
+			}
+		}
+
+		[TestMethod]
+		public void TestThrowsOnUnix()
+		{
+			if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+				return;
+			var postWriteHandler = new PosixPostWriteHandler();
+			var tmpFile = Path.GetTempFileName();
+			File.Delete(tmpFile);
+			Assert.ThrowsException<UnixIOException>(() => postWriteHandler.HandleWrite(tmpFile));
+			Directory.CreateDirectory(tmpFile);
+			try
+			{
+				//can't +x a directory ;) (taps head)
+				Assert.ThrowsException<UnixIOException>(() => postWriteHandler.HandleWrite(tmpFile));
+			}
+			finally
+			{
+				File.Delete(tmpFile);
+			}
+		}
+	}
+}