diff --git a/tests/Avalonia.Animation.UnitTests/Avalonia.Animation.UnitTests.csproj b/tests/Avalonia.Animation.UnitTests/Avalonia.Animation.UnitTests.csproj
index 1b2ba3c7de..ef515ce155 100644
--- a/tests/Avalonia.Animation.UnitTests/Avalonia.Animation.UnitTests.csproj
+++ b/tests/Avalonia.Animation.UnitTests/Avalonia.Animation.UnitTests.csproj
@@ -1,9 +1,11 @@
 <Project Sdk="Microsoft.NET.Sdk" ToolsVersion="15.0">
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp2.0</TargetFrameworks>
+    <TargetFrameworks>netcoreapp2.0;net47</TargetFrameworks>
     <OutputType>Library</OutputType>
+    <IsTestProject>true</IsTestProject>
   </PropertyGroup>
   <Import Project="..\..\build\UnitTests.NetCore.targets" />
+  <Import Project="..\..\build\UnitTests.NetFX.props" />
   <Import Project="..\..\build\Moq.props" />
   <Import Project="..\..\build\XUnit.props" />
   <Import Project="..\..\build\Rx.props" />
@@ -22,4 +24,4 @@
   <ItemGroup>
     <Service Include="{82a7f48d-3b50-4b1e-b82e-3ada8210c358}" />
   </ItemGroup>
-</Project>
\ No newline at end of file
+</Project>
diff --git a/tests/Avalonia.Base.UnitTests/Data/Core/ExpressionObserverTests_Property.cs b/tests/Avalonia.Base.UnitTests/Data/Core/ExpressionObserverTests_Property.cs
index c90683959e..239c9d56aa 100644
--- a/tests/Avalonia.Base.UnitTests/Data/Core/ExpressionObserverTests_Property.cs
+++ b/tests/Avalonia.Base.UnitTests/Data/Core/ExpressionObserverTests_Property.cs
@@ -558,7 +558,12 @@ namespace Avalonia.Base.UnitTests.Data.Core
             var result = run();
             result.Item1.Subscribe(x => { });
 
-            GC.Collect();
+            // Mono trickery
+            GC.Collect(2);
+            GC.WaitForPendingFinalizers();
+            GC.WaitForPendingFinalizers();
+            GC.Collect(2);
+            
 
             Assert.Null(result.Item2.Target);
         }
diff --git a/tests/Avalonia.Input.UnitTests/Avalonia.Input.UnitTests.csproj b/tests/Avalonia.Input.UnitTests/Avalonia.Input.UnitTests.csproj
index 1b2ba3c7de..ef515ce155 100644
--- a/tests/Avalonia.Input.UnitTests/Avalonia.Input.UnitTests.csproj
+++ b/tests/Avalonia.Input.UnitTests/Avalonia.Input.UnitTests.csproj
@@ -1,9 +1,11 @@
 <Project Sdk="Microsoft.NET.Sdk" ToolsVersion="15.0">
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp2.0</TargetFrameworks>
+    <TargetFrameworks>netcoreapp2.0;net47</TargetFrameworks>
     <OutputType>Library</OutputType>
+    <IsTestProject>true</IsTestProject>
   </PropertyGroup>
   <Import Project="..\..\build\UnitTests.NetCore.targets" />
+  <Import Project="..\..\build\UnitTests.NetFX.props" />
   <Import Project="..\..\build\Moq.props" />
   <Import Project="..\..\build\XUnit.props" />
   <Import Project="..\..\build\Rx.props" />
@@ -22,4 +24,4 @@
   <ItemGroup>
     <Service Include="{82a7f48d-3b50-4b1e-b82e-3ada8210c358}" />
   </ItemGroup>
-</Project>
\ No newline at end of file
+</Project>
diff --git a/tests/Avalonia.Interactivity.UnitTests/Avalonia.Interactivity.UnitTests.csproj b/tests/Avalonia.Interactivity.UnitTests/Avalonia.Interactivity.UnitTests.csproj
index bc883d0251..6b19d81034 100644
--- a/tests/Avalonia.Interactivity.UnitTests/Avalonia.Interactivity.UnitTests.csproj
+++ b/tests/Avalonia.Interactivity.UnitTests/Avalonia.Interactivity.UnitTests.csproj
@@ -1,9 +1,12 @@
 <Project Sdk="Microsoft.NET.Sdk" ToolsVersion="15.0">
   <PropertyGroup>
     <TargetFrameworks>netcoreapp2.0</TargetFrameworks>
+    <TargetFrameworks>netcoreapp2.0;net47</TargetFrameworks>
     <OutputType>Library</OutputType>
+    <IsTestProject>true</IsTestProject>
   </PropertyGroup>
   <Import Project="..\..\build\UnitTests.NetCore.targets" />
+  <Import Project="..\..\build\UnitTests.NetFX.props" />
   <Import Project="..\..\build\XUnit.props" />
   <Import Project="..\..\build\Rx.props" />
   <Import Project="..\..\build\Microsoft.Reactive.Testing.props" />
@@ -20,4 +23,4 @@
   <ItemGroup>
     <Service Include="{82A7F48D-3B50-4B1E-B82E-3ADA8210C358}" />
   </ItemGroup>
-</Project>
\ No newline at end of file
+</Project>
diff --git a/tests/Avalonia.Markup.UnitTests/Avalonia.Markup.UnitTests.csproj b/tests/Avalonia.Markup.UnitTests/Avalonia.Markup.UnitTests.csproj
index 1680ecf798..aba5f2d469 100644
--- a/tests/Avalonia.Markup.UnitTests/Avalonia.Markup.UnitTests.csproj
+++ b/tests/Avalonia.Markup.UnitTests/Avalonia.Markup.UnitTests.csproj
@@ -1,9 +1,11 @@
 <Project Sdk="Microsoft.NET.Sdk" ToolsVersion="15.0">
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp2.0</TargetFrameworks>
+    <TargetFrameworks>netcoreapp2.0;net47</TargetFrameworks>
     <OutputType>Library</OutputType>
+    <IsTestProject>true</IsTestProject>
   </PropertyGroup>
   <Import Project="..\..\build\UnitTests.NetCore.targets" />
+  <Import Project="..\..\build\UnitTests.NetFX.props" />
   <Import Project="..\..\build\Moq.props" />
   <Import Project="..\..\build\XUnit.props" />
   <Import Project="..\..\build\Rx.props" />
@@ -23,4 +25,4 @@
   <ItemGroup>
     <Service Include="{82A7F48D-3B50-4B1E-B82E-3ADA8210C358}" />
   </ItemGroup>
-</Project>
\ No newline at end of file
+</Project>
diff --git a/tests/Avalonia.Markup.Xaml.UnitTests/Avalonia.Markup.Xaml.UnitTests.csproj b/tests/Avalonia.Markup.Xaml.UnitTests/Avalonia.Markup.Xaml.UnitTests.csproj
index 735d5c421a..8b47bcec30 100644
--- a/tests/Avalonia.Markup.Xaml.UnitTests/Avalonia.Markup.Xaml.UnitTests.csproj
+++ b/tests/Avalonia.Markup.Xaml.UnitTests/Avalonia.Markup.Xaml.UnitTests.csproj
@@ -1,9 +1,11 @@
 <Project Sdk="Microsoft.NET.Sdk" ToolsVersion="15.0">
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp2.0</TargetFrameworks>
+    <TargetFrameworks>netcoreapp2.0;net47</TargetFrameworks>
     <OutputType>Library</OutputType>
+    <IsTestProject>true</IsTestProject>
   </PropertyGroup>
   <Import Project="..\..\build\UnitTests.NetCore.targets" />
+  <Import Project="..\..\build\UnitTests.NetFX.props" />
   <Import Project="..\..\build\Moq.props" />
   <Import Project="..\..\build\XUnit.props" />
   <Import Project="..\..\build\Rx.props" />
@@ -36,4 +38,4 @@
   <ItemGroup>
     <Service Include="{82A7F48D-3B50-4B1E-B82E-3ADA8210C358}" />
   </ItemGroup>
-</Project>
\ No newline at end of file
+</Project>
diff --git a/tests/Avalonia.Styling.UnitTests/Avalonia.Styling.UnitTests.csproj b/tests/Avalonia.Styling.UnitTests/Avalonia.Styling.UnitTests.csproj
index e65dd848dd..3fd280f7ab 100644
--- a/tests/Avalonia.Styling.UnitTests/Avalonia.Styling.UnitTests.csproj
+++ b/tests/Avalonia.Styling.UnitTests/Avalonia.Styling.UnitTests.csproj
@@ -1,10 +1,12 @@
 <Project Sdk="Microsoft.NET.Sdk" ToolsVersion="15.0">
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp2.0</TargetFrameworks>
+    <TargetFrameworks>netcoreapp2.0;net47</TargetFrameworks>
     <OutputType>Library</OutputType>
     <NoWarn>CS0067</NoWarn>
+    <IsTestProject>true</IsTestProject>
   </PropertyGroup>
   <Import Project="..\..\build\UnitTests.NetCore.targets" />
+  <Import Project="..\..\build\UnitTests.NetFX.props" />
   <Import Project="..\..\build\Moq.props" />
   <Import Project="..\..\build\XUnit.props" />
   <Import Project="..\..\build\Rx.props" />
@@ -23,4 +25,4 @@
   <ItemGroup>
     <Service Include="{82A7F48D-3B50-4B1E-B82E-3ADA8210C358}" />
   </ItemGroup>
-</Project>
\ No newline at end of file
+</Project>
diff --git a/tests/Avalonia.Visuals.UnitTests/Avalonia.Visuals.UnitTests.csproj b/tests/Avalonia.Visuals.UnitTests/Avalonia.Visuals.UnitTests.csproj
index 2b559c9c56..50c2e580b0 100644
--- a/tests/Avalonia.Visuals.UnitTests/Avalonia.Visuals.UnitTests.csproj
+++ b/tests/Avalonia.Visuals.UnitTests/Avalonia.Visuals.UnitTests.csproj
@@ -1,8 +1,11 @@
 <Project Sdk="Microsoft.NET.Sdk" ToolsVersion="15.0">
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp2.0</TargetFrameworks>
+    <TargetFrameworks>netcoreapp2.0;net47</TargetFrameworks>
+    <OutputType>Library</OutputType>
+    <IsTestProject>true</IsTestProject>
   </PropertyGroup>
   <Import Project="..\..\build\UnitTests.NetCore.targets" />
+  <Import Project="..\..\build\UnitTests.NetFX.props" />
   <Import Project="..\..\build\Moq.props" />
   <Import Project="..\..\build\XUnit.props" />
   <Import Project="..\..\build\Rx.props" />
@@ -21,4 +24,4 @@
   <ItemGroup>
     <Service Include="{82A7F48D-3B50-4B1E-B82E-3ADA8210C358}" />
   </ItemGroup>
-</Project>
\ No newline at end of file
+</Project>