The test projects won't restore under dotnet 10

Author: GrahamTheCoder

.github/workflows/dotnet-tests.yml

@@ -32,9 +32,37 @@ jobs:
     - name: Build
       run: dotnet build DotNetBuildable.slnf /p:Configuration=Release
 
-    - name: Create global.json to enforce .NET 8 for MSBuild
+    - name: Create global.json to enforce .NET 8 for MSBuild and update Tests/TestData projects
       if: inputs.dotnet-version == '8.0.x'
-      run: echo '{"sdk":{"version":"8.0.0","rollForward":"latestFeature"}}' > global.json
+      shell: pwsh
+      run: |
+        # ensure .NET 8 SDK is used for MSBuild operations
+        '{"sdk":{"version":"8.0.0","rollForward":"latestFeature"}}' | Out-File -FilePath global.json -Encoding utf8
+        Write-Host "Updating <TargetFramework>net10.0...</TargetFramework> entries to net8.0 under Tests/TestData"
+
+        # Replace net10.0 and net10.0-windows with net8.0 / net8.0-windows respectively
+        $projFiles = Get-ChildItem -Path Tests/TestData -Recurse -Include *.csproj,*.vbproj,*.fsproj -ErrorAction SilentlyContinue
+        foreach ($f in $projFiles) {
+          $path = $f.FullName
+          $content = Get-Content -Path $path -Raw -ErrorAction Stop
+          $updated = $content -replace '<TargetFramework>net10.0(-windows)?</TargetFramework>', '<TargetFramework>net8.0$1</TargetFramework>'
+          if ($updated -ne $content) {
+            Write-Host "Updating: $path"
+            $updated | Set-Content -Path $path -Encoding utf8
+          }
+        }
+
+        # If any files were changed, commit them so the working tree is clean for subsequent test steps.
+        $status = git status --porcelain
+        if ($status) {
+          git config user.name "github-actions[bot]"
+          git config user.email "${{ github.actor }}@users.noreply.github.com"
+          git add -A
+          git commit -m "CI: Update Tests/TestData TargetFramework -> net8.0 for .NET 8 run" || Write-Host "git commit returned non-zero (possibly no staged changes)"
+          Write-Host "Committed changes to local repo (not pushed)."
+        } else {
+          Write-Host "No project files needed updating."
+        }
 
     - name: Log MSBuild version
       run: msbuild -version