fix: bound and configure tunnel quality probes (#533)

Closes #528 and #532.

go-backend/internal/monitoring/tunnel_quality_test.go

@@ -0,0 +1,37 @@
+package monitoring
+
+import "testing"
+
+func TestTunnelQualityProbeIntervalSecondsFromConfigMap(t *testing.T) {
+	tests := []struct {
+		name string
+		cfg  map[string]string
+		want int
+	}{
+		{name: "missing config", cfg: nil, want: DefaultTunnelQualityProbeIntervalSec},
+		{name: "configured", cfg: map[string]string{ConfigTunnelQualityProbeIntervalSec: "15"}, want: 15},
+		{name: "invalid", cfg: map[string]string{ConfigTunnelQualityProbeIntervalSec: "0"}, want: DefaultTunnelQualityProbeIntervalSec},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := TunnelQualityProbeIntervalSecondsFromConfigMap(tt.cfg); got != tt.want {
+				t.Fatalf("interval = %d, want %d", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestNormalizeTunnelQualityProbeIntervalSeconds(t *testing.T) {
+	for _, value := range []string{"1", "15", "3600"} {
+		if got, err := NormalizeTunnelQualityProbeIntervalSeconds(value); err != nil || got != value {
+			t.Fatalf("normalize %q = %q, %v", value, got, err)
+		}
+	}
+
+	for _, value := range []string{"", "0", "3601", "1.5", "abc"} {
+		if got, err := NormalizeTunnelQualityProbeIntervalSeconds(value); err == nil {
+			t.Fatalf("normalize %q unexpectedly succeeded with %q", value, got)
+		}
+	}
+}