feat(go): add 100k ingest hardening baseline

go/vehicle-gateway/cmd/load-sim/main_test.go

@@ -0,0 +1,28 @@
+package main
+
+import (
+	"strings"
+	"testing"
+
+	"lingniu-vehicle-ingest/go/vehicle-gateway/internal/loadsim"
+)
+
+func TestFormatStatsIncludesCapacityCounters(t *testing.T) {
+	out := formatStats(loadsim.Stats{
+		ConnectionsOpened: 10,
+		ConnectionsFailed: 2,
+		FramesWritten:     300,
+		WriteErrors:       1,
+	})
+
+	for _, want := range []string{
+		"connections_opened=10",
+		"connections_failed=2",
+		"frames_written=300",
+		"write_errors=1",
+	} {
+		if !strings.Contains(out, want) {
+			t.Fatalf("formatStats() = %q, missing %q", out, want)
+		}
+	}
+}