diff --git a/src/TestabilityKata.Tests/CustomFileWriterTest.cs b/src/TestabilityKata.Tests/CustomFileWriterTest.cs
new file mode 100644
index 0000000..b0cf46c
--- /dev/null
+++ b/src/TestabilityKata.Tests/CustomFileWriterTest.cs
@@ -0,0 +1,40 @@
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using NSubstitute;
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Text;
+
+namespace TestabilityKata.Tests
+{
+    [TestClass]
+    public class CustomFileWriterTest
+    {
+        [TestMethod]
+        public void WhenCreatingFileAnEmailIsSentOut()
+        {
+            var fakeMailSender = Substitute.For<IMailSender>();
+
+            const string testFilePath = @"C:\WhenCreatingFileAnEmailIsSentOut.txt";
+
+            //if the existing file exists, delete it before running the test, since
+            //we need to get to the point where a new file is created.
+            if(File.Exists(testFilePath))
+            {
+                File.SetAttributes(testFilePath, FileAttributes.Normal);
+                File.Delete(testFilePath);
+            }
+
+            var customFileWriter = new CustomFileWriter(
+                fakeMailSender,
+                testFilePath);
+            customFileWriter.AppendLine("Some line");
+
+            fakeMailSender
+                .Received()
+                .SendMail(
+                    Arg.Any<string>(),
+                    Arg.Any<string>());
+        }
+    }
+}
diff --git a/src/TestabilityKata.Tests/TestabilityKata.Tests.csproj b/src/TestabilityKata.Tests/TestabilityKata.Tests.csproj
index f8c14f3..14ce7f0 100644
--- a/src/TestabilityKata.Tests/TestabilityKata.Tests.csproj
+++ b/src/TestabilityKata.Tests/TestabilityKata.Tests.csproj
@@ -1,17 +1,17 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>netcoreapp2.0</TargetFramework>
+    <TargetFramework>net6.0</TargetFramework>
 
     <IsPackable>false</IsPackable>
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="FluffySpoon.Testing.Autofake.Autofac" Version="1.0.5" />
-    <PackageReference Include="FluffySpoon.Testing.Autofake.NSubstitute" Version="1.0.5" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.3.0-preview-20170628-02" />
-    <PackageReference Include="MSTest.TestAdapter" Version="1.1.18" />
-    <PackageReference Include="MSTest.TestFramework" Version="1.1.18" />
+    <PackageReference Include="FluffySpoon.Testing.Autofake.Autofac" Version="1.34.0" />
+    <PackageReference Include="FluffySpoon.Testing.Autofake.NSubstitute" Version="1.34.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.2.0" />
+    <PackageReference Include="MSTest.TestAdapter" Version="2.2.10" />
+    <PackageReference Include="MSTest.TestFramework" Version="2.2.10" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/src/TestabilityKata/TestabilityKata.csproj b/src/TestabilityKata/TestabilityKata.csproj
index ce1697a..41f1d5a 100644
--- a/src/TestabilityKata/TestabilityKata.csproj
+++ b/src/TestabilityKata/TestabilityKata.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>netcoreapp2.0</TargetFramework>
+    <TargetFramework>net6.0</TargetFramework>
   </PropertyGroup>
 
 </Project>