diff --git a/EnvelopeGenerator.Tests/EnvelopeGenerator.Tests.csproj b/EnvelopeGenerator.Tests/EnvelopeGenerator.Tests.csproj
new file mode 100644
index 00000000..c30d81d9
--- /dev/null
+++ b/EnvelopeGenerator.Tests/EnvelopeGenerator.Tests.csproj
@@ -0,0 +1,24 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFrameworks>net7.0;net8.0</TargetFrameworks>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+
+    <IsPackable>false</IsPackable>
+    <IsTestProject>true</IsTestProject>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="coverlet.collector" Version="6.0.0" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
+    <PackageReference Include="NUnit" Version="3.14.0" />
+    <PackageReference Include="NUnit.Analyzers" Version="3.9.0" />
+    <PackageReference Include="NUnit3TestAdapter" Version="4.5.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Using Include="NUnit.Framework" />
+  </ItemGroup>
+
+</Project>
diff --git a/EnvelopeGenerator.sln b/EnvelopeGenerator.sln
index 3e6fecaf..24dc590d 100644
--- a/EnvelopeGenerator.sln
+++ b/EnvelopeGenerator.sln
@@ -29,6 +29,8 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "src", "src", "{134D4164-B29
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "tests", "tests", "{0CBC2432-A561-4440-89BC-671B66A24146}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "EnvelopeGenerator.Tests", "EnvelopeGenerator.Tests\EnvelopeGenerator.Tests.csproj", "{A4D0DD1A-67BC-4E1A-AD29-BC4BC0D41399}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -75,6 +77,10 @@ Global
 		{47F98812-4280-4D53-B04A-2AAEEA5EBC31}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{47F98812-4280-4D53-B04A-2AAEEA5EBC31}.Release|Any CPU.ActiveCfg = Debug|Any CPU
 		{47F98812-4280-4D53-B04A-2AAEEA5EBC31}.Release|Any CPU.Build.0 = Debug|Any CPU
+		{A4D0DD1A-67BC-4E1A-AD29-BC4BC0D41399}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{A4D0DD1A-67BC-4E1A-AD29-BC4BC0D41399}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{A4D0DD1A-67BC-4E1A-AD29-BC4BC0D41399}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{A4D0DD1A-67BC-4E1A-AD29-BC4BC0D41399}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -91,6 +97,7 @@ Global
 		{E5E12BA4-60C1-48BA-9053-0F8B62B38124} = {134D4164-B291-4E19-99B9-E4FA3AFAB62C}
 		{47F98812-4280-4D53-B04A-2AAEEA5EBC31} = {134D4164-B291-4E19-99B9-E4FA3AFAB62C}
 		{9943209E-1744-4944-B1BA-4F87FC1A0EEB} = {134D4164-B291-4E19-99B9-E4FA3AFAB62C}
+		{A4D0DD1A-67BC-4E1A-AD29-BC4BC0D41399} = {0CBC2432-A561-4440-89BC-671B66A24146}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {73E60370-756D-45AD-A19A-C40A02DACCC7}