Fail fast in run-unit-tests: stop at first failing project

Previously the script ran every unit-test project and only reported the
aggregate failures at the end. Exit immediately on the first failing
project for quicker feedback and to avoid spending CI time on later
projects once the build is already red.

Author: GarrettBeatty

buildtools/run-unit-tests.ps1

@@ -43,7 +43,6 @@ if (-not $projects)
 Write-Host "Running $($projects.Count) unit-test project(s):"
 $projects | ForEach-Object { Write-Host "  - $_" }
 
-$failed = @()
 foreach ($project in $projects)
 {
     $name = [System.IO.Path]::GetFileNameWithoutExtension($project)
@@ -52,18 +51,13 @@ foreach ($project in $projects)
     dotnet test -c $Configuration $project
     if ($LASTEXITCODE -ne 0)
     {
-        Write-Host "Tests failed for $name (exit $LASTEXITCODE)."
-        $failed += $name
+        # Fail fast: stop at the first failing project rather than running the rest. This gives
+        # quicker feedback and avoids spending CI time on later projects once the build is red.
+        Write-Host ""
+        Write-Host "Tests failed for $name (exit $LASTEXITCODE). Stopping without running the remaining project(s)."
+        exit 1
     }
 }
 
-if ($failed)
-{
-    Write-Host ""
-    Write-Host "The following unit-test project(s) failed:"
-    $failed | ForEach-Object { Write-Host "  - $_" }
-    exit 1
-}
-
 Write-Host ""
 Write-Host "All unit-test projects passed."