Skip .NET Framework tests on non-Windows platforms

- Configure TargetFrameworks to conditionally include net472 only on Windows
- Remove mono setup steps from CI workflow

Co-authored-by: stephentoub <2642209+stephentoub@users.noreply.github.com>

Author: Copilot

.github/workflows/ci-build-test.yml

@@ -47,15 +47,6 @@ jobs:
           10.0.x
           9.0.x
 
-    # NetFX testing on non-Windows requires mono
-    - name: 🔧 Setup Mono
-      if: runner.os == 'Linux'
-      run: sudo apt-get install -y mono-devel
-
-    - name: 🔧 Setup Mono on macOS
-      if: runner.os == 'macOS'
-      run: brew install mono
-
     - name: 🔧 Set up Node.js
       uses: actions/setup-node@6044e13b5dc448c55e2357c09f80417699197238 # v6.2.0
       with:

samples/TestServerWithHosting/TestServerWithHosting.csproj

@@ -2,7 +2,8 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFrameworks>net10.0;net9.0;net8.0;net472</TargetFrameworks>
+    <TargetFrameworks>net10.0;net9.0;net8.0</TargetFrameworks>
+    <TargetFrameworks Condition="$([MSBuild]::IsOSPlatform('Windows'))">$(TargetFrameworks);net472</TargetFrameworks>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
     <PublishAot Condition="'$(TargetFramework)' == 'net9.0'">true</PublishAot>

tests/ModelContextProtocol.TestServer/ModelContextProtocol.TestServer.csproj

@@ -2,7 +2,8 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFrameworks>net10.0;net9.0;net8.0;net472</TargetFrameworks>
+    <TargetFrameworks>net10.0;net9.0;net8.0</TargetFrameworks>
+    <TargetFrameworks Condition="$([MSBuild]::IsOSPlatform('Windows'))">$(TargetFrameworks);net472</TargetFrameworks>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
     <AssemblyName>TestServer</AssemblyName>

tests/ModelContextProtocol.Tests/ModelContextProtocol.Tests.csproj

@@ -2,7 +2,8 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFrameworks>net10.0;net9.0;net8.0;net472</TargetFrameworks>
+    <TargetFrameworks>net10.0;net9.0;net8.0</TargetFrameworks>
+    <TargetFrameworks Condition="$([MSBuild]::IsOSPlatform('Windows'))">$(TargetFrameworks);net472</TargetFrameworks>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>