fix(stress): label loaders and improve john opencl diagnostics

audit/internal/platform/sat_test.go

@@ -162,6 +162,25 @@ func TestBuildNvidiaStressJobUsesNCCLLoader(t *testing.T) {
 	}
 }
 
+func TestNvidiaStressArchivePrefixByLoader(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		loader string
+		want   string
+	}{
+		{loader: NvidiaStressLoaderBuiltin, want: "gpu-nvidia-burn"},
+		{loader: NvidiaStressLoaderJohn, want: "gpu-nvidia-john"},
+		{loader: NvidiaStressLoaderNCCL, want: "gpu-nvidia-nccl"},
+		{loader: "", want: "gpu-nvidia-burn"},
+	}
+	for _, tt := range tests {
+		if got := nvidiaStressArchivePrefix(tt.loader); got != tt.want {
+			t.Fatalf("loader=%q prefix=%q want %q", tt.loader, got, tt.want)
+		}
+	}
+}
+
 func TestEnvIntFallback(t *testing.T) {
 	os.Unsetenv("BEE_MEMTESTER_SIZE_MB")
 	if got := envInt("BEE_MEMTESTER_SIZE_MB", 123); got != 123 {