diff --git a/csharp/src/Google.Protobuf.Test.CodeGen/ForeignMessagePartial.cs b/csharp/src/Google.Protobuf.Test.TestProtos/ForeignMessagePartial.cs
similarity index 100%
rename from csharp/src/Google.Protobuf.Test.CodeGen/ForeignMessagePartial.cs
rename to csharp/src/Google.Protobuf.Test.TestProtos/ForeignMessagePartial.cs
diff --git a/csharp/src/Google.Protobuf.Test.CodeGen/Google.Protobuf.Test.CodeGen.csproj b/csharp/src/Google.Protobuf.Test.TestProtos/Google.Protobuf.Test.TestProtos.csproj
similarity index 75%
rename from csharp/src/Google.Protobuf.Test.CodeGen/Google.Protobuf.Test.CodeGen.csproj
rename to csharp/src/Google.Protobuf.Test.TestProtos/Google.Protobuf.Test.TestProtos.csproj
index d756b0f757..4de9fe6723 100644
--- a/csharp/src/Google.Protobuf.Test.CodeGen/Google.Protobuf.Test.CodeGen.csproj
+++ b/csharp/src/Google.Protobuf.Test.TestProtos/Google.Protobuf.Test.TestProtos.csproj
@@ -14,6 +14,11 @@
     <IsPackable>False</IsPackable>
   </PropertyGroup>
 
+  <!-- Needed for the net45 build to work on Unix. See https://github.com/dotnet/designs/pull/33 -->
+  <ItemGroup>
+    <PackageReference Include="Microsoft.NETFramework.ReferenceAssemblies" Version="1.0.0-preview.2" PrivateAssets="All" />
+  </ItemGroup>
+  
   <ItemGroup>
     <ProjectReference Include="..\Google.Protobuf\Google.Protobuf.csproj" />
   </ItemGroup>
diff --git a/csharp/src/Google.Protobuf.Test.CodeGen/MapUnittestProto3.cs b/csharp/src/Google.Protobuf.Test.TestProtos/MapUnittestProto3.cs
similarity index 100%
rename from csharp/src/Google.Protobuf.Test.CodeGen/MapUnittestProto3.cs
rename to csharp/src/Google.Protobuf.Test.TestProtos/MapUnittestProto3.cs
diff --git a/csharp/src/Google.Protobuf.Test.CodeGen/OldExtensions1.cs b/csharp/src/Google.Protobuf.Test.TestProtos/OldExtensions1.cs
similarity index 100%
rename from csharp/src/Google.Protobuf.Test.CodeGen/OldExtensions1.cs
rename to csharp/src/Google.Protobuf.Test.TestProtos/OldExtensions1.cs
diff --git a/csharp/src/Google.Protobuf.Test.CodeGen/OldExtensions2.cs b/csharp/src/Google.Protobuf.Test.TestProtos/OldExtensions2.cs
similarity index 100%
rename from csharp/src/Google.Protobuf.Test.CodeGen/OldExtensions2.cs
rename to csharp/src/Google.Protobuf.Test.TestProtos/OldExtensions2.cs
diff --git a/csharp/src/Google.Protobuf.Test.CodeGen/TestMessagesProto2.cs b/csharp/src/Google.Protobuf.Test.TestProtos/TestMessagesProto2.cs
similarity index 100%
rename from csharp/src/Google.Protobuf.Test.CodeGen/TestMessagesProto2.cs
rename to csharp/src/Google.Protobuf.Test.TestProtos/TestMessagesProto2.cs
diff --git a/csharp/src/Google.Protobuf.Test.CodeGen/TestMessagesProto3.cs b/csharp/src/Google.Protobuf.Test.TestProtos/TestMessagesProto3.cs
similarity index 100%
rename from csharp/src/Google.Protobuf.Test.CodeGen/TestMessagesProto3.cs
rename to csharp/src/Google.Protobuf.Test.TestProtos/TestMessagesProto3.cs
diff --git a/csharp/src/Google.Protobuf.Test.CodeGen/Unittest.cs b/csharp/src/Google.Protobuf.Test.TestProtos/Unittest.cs
similarity index 100%
rename from csharp/src/Google.Protobuf.Test.CodeGen/Unittest.cs
rename to csharp/src/Google.Protobuf.Test.TestProtos/Unittest.cs
diff --git a/csharp/src/Google.Protobuf.Test.CodeGen/UnittestCustomOptionsProto3.cs b/csharp/src/Google.Protobuf.Test.TestProtos/UnittestCustomOptionsProto3.cs
similarity index 100%
rename from csharp/src/Google.Protobuf.Test.CodeGen/UnittestCustomOptionsProto3.cs
rename to csharp/src/Google.Protobuf.Test.TestProtos/UnittestCustomOptionsProto3.cs
diff --git a/csharp/src/Google.Protobuf.Test.CodeGen/UnittestImport.cs b/csharp/src/Google.Protobuf.Test.TestProtos/UnittestImport.cs
similarity index 100%
rename from csharp/src/Google.Protobuf.Test.CodeGen/UnittestImport.cs
rename to csharp/src/Google.Protobuf.Test.TestProtos/UnittestImport.cs
diff --git a/csharp/src/Google.Protobuf.Test.CodeGen/UnittestImportProto3.cs b/csharp/src/Google.Protobuf.Test.TestProtos/UnittestImportProto3.cs
similarity index 100%
rename from csharp/src/Google.Protobuf.Test.CodeGen/UnittestImportProto3.cs
rename to csharp/src/Google.Protobuf.Test.TestProtos/UnittestImportProto3.cs
diff --git a/csharp/src/Google.Protobuf.Test.CodeGen/UnittestImportPublic.cs b/csharp/src/Google.Protobuf.Test.TestProtos/UnittestImportPublic.cs
similarity index 100%
rename from csharp/src/Google.Protobuf.Test.CodeGen/UnittestImportPublic.cs
rename to csharp/src/Google.Protobuf.Test.TestProtos/UnittestImportPublic.cs
diff --git a/csharp/src/Google.Protobuf.Test.CodeGen/UnittestImportPublicProto3.cs b/csharp/src/Google.Protobuf.Test.TestProtos/UnittestImportPublicProto3.cs
similarity index 100%
rename from csharp/src/Google.Protobuf.Test.CodeGen/UnittestImportPublicProto3.cs
rename to csharp/src/Google.Protobuf.Test.TestProtos/UnittestImportPublicProto3.cs
diff --git a/csharp/src/Google.Protobuf.Test.CodeGen/UnittestIssues.cs b/csharp/src/Google.Protobuf.Test.TestProtos/UnittestIssues.cs
similarity index 100%
rename from csharp/src/Google.Protobuf.Test.CodeGen/UnittestIssues.cs
rename to csharp/src/Google.Protobuf.Test.TestProtos/UnittestIssues.cs
diff --git a/csharp/src/Google.Protobuf.Test.CodeGen/UnittestProto3.cs b/csharp/src/Google.Protobuf.Test.TestProtos/UnittestProto3.cs
similarity index 100%
rename from csharp/src/Google.Protobuf.Test.CodeGen/UnittestProto3.cs
rename to csharp/src/Google.Protobuf.Test.TestProtos/UnittestProto3.cs
diff --git a/csharp/src/Google.Protobuf.Test.CodeGen/UnittestWellKnownTypes.cs b/csharp/src/Google.Protobuf.Test.TestProtos/UnittestWellKnownTypes.cs
similarity index 100%
rename from csharp/src/Google.Protobuf.Test.CodeGen/UnittestWellKnownTypes.cs
rename to csharp/src/Google.Protobuf.Test.TestProtos/UnittestWellKnownTypes.cs
diff --git a/csharp/src/Google.Protobuf.Test/Google.Protobuf.Test.csproj b/csharp/src/Google.Protobuf.Test/Google.Protobuf.Test.csproj
index 102c7acf2b..1a7953d6b7 100644
--- a/csharp/src/Google.Protobuf.Test/Google.Protobuf.Test.csproj
+++ b/csharp/src/Google.Protobuf.Test/Google.Protobuf.Test.csproj
@@ -10,7 +10,7 @@
 
   <ItemGroup>
     <ProjectReference Include="..\Google.Protobuf\Google.Protobuf.csproj" />
-    <ProjectReference Include="..\Google.Protobuf.Test.CodeGen\Google.Protobuf.Test.CodeGen.csproj"/>
+    <ProjectReference Include="..\Google.Protobuf.Test.TestProtos\Google.Protobuf.Test.TestProtos.csproj"/>
   </ItemGroup>
 
   <ItemGroup>