inbounds: allow custom monthly traffic reset days (#6071)

internal/web/service/inbound_traffic_reset_test.go

@@ -0,0 +1,18 @@
+package service
+
+import "testing"
+
+func TestNormalizeTrafficResetDay(t *testing.T) {
+	tests := map[int]int{
+		0:  1,
+		1:  1,
+		15: 15,
+		31: 31,
+		32: 31,
+	}
+	for input, want := range tests {
+		if got := normalizeTrafficResetDay(input); got != want {
+			t.Errorf("normalizeTrafficResetDay(%d) = %d, want %d", input, got, want)
+		}
+	}
+}