extract utility method

a method to send json over tcp can be used by several tests

pdb-plotting/src/main/java/org/lucares/pdb/plot/api/PlotSettings.java

@@ -105,12 +105,12 @@ public class PlotSettings {
 
 	public OffsetDateTime dateTo() {
 
-		final int period = Integer.parseInt(dateRange.split(" ")[0]);
-		final ChronoUnit unit = toChronoUnit(dateRange.split(" ")[1]);
-
 		if (StringUtils.isEmpty(dateRange)) {
 			return OffsetDateTime.ofInstant(Instant.ofEpochMilli(Long.MAX_VALUE), ZoneOffset.UTC);
 		} else {
+			final int period = Integer.parseInt(dateRange.split(" ")[0]);
+			final ChronoUnit unit = toChronoUnit(dateRange.split(" ")[1]);
+
 			return dateFrom().plus(period, unit);
 		}
 	}