fix(stress): keep platform burn responsive under load

audit/internal/platform/platform_stress_test.go

@@ -0,0 +1,34 @@
+package platform
+
+import (
+	"runtime"
+	"testing"
+)
+
+func TestPlatformStressCPUThreadsOverride(t *testing.T) {
+	t.Setenv("BEE_PLATFORM_STRESS_THREADS", "7")
+	if got := platformStressCPUThreads(); got != 7 {
+		t.Fatalf("platformStressCPUThreads=%d want 7", got)
+	}
+}
+
+func TestPlatformStressCPUThreadsDefaultLeavesHeadroom(t *testing.T) {
+	t.Setenv("BEE_PLATFORM_STRESS_THREADS", "")
+	got := platformStressCPUThreads()
+	if got < 1 {
+		t.Fatalf("platformStressCPUThreads=%d want >= 1", got)
+	}
+	if got > runtime.NumCPU() {
+		t.Fatalf("platformStressCPUThreads=%d want <= NumCPU=%d", got, runtime.NumCPU())
+	}
+	if runtime.NumCPU() > 2 && got >= runtime.NumCPU() {
+		t.Fatalf("platformStressCPUThreads=%d want headroom below NumCPU=%d", got, runtime.NumCPU())
+	}
+}
+
+func TestPlatformStressMemoryMBOverride(t *testing.T) {
+	t.Setenv("BEE_PLATFORM_STRESS_MB", "8192")
+	if got := platformStressMemoryMB(); got != 8192 {
+		t.Fatalf("platformStressMemoryMB=%d want 8192", got)
+	}
+}