fix(tests): disable MSBuild node reuse for spawned builds

tests/Tenekon.MethodOverloads.SourceGenerator.Tests/Infrastructure/PackageLayoutFixture.cs

@@ -53,14 +53,20 @@ private static ProcessResult RunProcess(string fileName, string arguments)
             CreateNoWindow = true
         };
 
+        // Reused MSBuild nodes outlive the build and inherit the redirected pipes, so reading
+        // stdout/stderr to the end would block until their idle timeout expires.
+        startInfo.Environment["MSBUILDDISABLENODEREUSE"] = "1";
+
         using var process = new Process { StartInfo = startInfo };
         process.Start();
 
+        // Drain both streams concurrently; reading them one after another can deadlock once the
+        // other pipe's buffer is full.
+        var error = process.StandardError.ReadToEndAsync();
         var output = process.StandardOutput.ReadToEnd();
-        var error = process.StandardError.ReadToEnd();
         process.WaitForExit();
 
-        return new ProcessResult(process.ExitCode, string.Concat(output, error));
+        return new ProcessResult(process.ExitCode, string.Concat(output, error.Result));
     }
 
     private sealed record ProcessResult(int ExitCode, string Output);

tests/Tenekon.MethodOverloads.SourceGenerator.Tests/RefProjectBuildTests.cs

@@ -66,6 +66,10 @@ private static ProcessResult RunProcess(
             CreateNoWindow = true
         };
 
+        // Reused MSBuild nodes outlive the build and inherit the redirected pipes, so reading
+        // stdout/stderr to the end would block until their idle timeout expires.
+        process.StartInfo.Environment["MSBUILDDISABLENODEREUSE"] = "1";
+
         process.Start();
         var stdOut = process.StandardOutput.ReadToEndAsync();
         var stdErr = process.StandardError.ReadToEndAsync();

tests/Tenekon.MethodOverloads.SourceGenerator.Tests/Tenekon.MethodOverloads.SourceGenerator.Tests.csproj

@@ -1,6 +1,8 @@
 <Project Sdk="Microsoft.NET.Sdk">
     <PropertyGroup>
         <TargetFramework>net8.0</TargetFramework>
+        <!-- Allow the tests to run where only a newer runtime is installed (e.g. the dotnet/sdk:10.0 CI image). -->
+        <RollForward>Major</RollForward>
         <LangVersion>preview</LangVersion>
         <Nullable>enable</Nullable>
         <ImplicitUsings>enable</ImplicitUsings>