Added some index checks and relavent Tests for them

src/main/java/seng202/group9/Core/Airline.java

@@ -2,6 +2,7 @@ package seng202.group9.Core;
 
 import seng202.group9.Controller.DataException;
 
+import javax.xml.crypto.Data;
 import java.util.ArrayList;
 
 /**
@@ -251,8 +252,12 @@ public class Airline{
 	 * deletes a route by matching index keep in mind that the array position will change for all indexs after this.
 	 * @param index
 	 */
-	public void delRoutes(int index){
-		routes.remove(index);
+	public void delRoutes(int index) throws DataException{
+		if (routes.size() > index && index >= 0) {
+			routes.remove(index);
+		}else{
+			throw new DataException("The Route at index "+index+ "does not exist to be deleted.");
+		}
 	}
 
 	/**

src/main/java/seng202/group9/Core/Airport.java

@@ -2,6 +2,7 @@ package seng202.group9.Core;
 
 import java.util.ArrayList;
 
+import javafx.scene.chart.PieChart;
 import seng202.group9.Controller.DataException;
 /**
  * Airport Class
@@ -363,8 +364,12 @@ public class Airport {
 	 * deletes a member of arrival routes by index
 	 * @param index
 	 */
-	public void delArrivalRoutes(int index){
-		arrivalRoutes.remove(index);
+	public void delArrivalRoutes(int index) throws DataException{
+		if (arrivalRoutes.size() > index && index >= 0) {
+			arrivalRoutes.remove(index);
+		}else{
+			throw new DataException("Index "+index+" of number of Arrival Routes array size.");
+		}
 	}
 	/**
 	 * deletes a member of departure routes by matching route pointer
@@ -378,8 +383,12 @@ public class Airport {
 	 * deletes a member of departure routes by index
 	 * @param index
 	 */
-	public void delDepartureRoutes(int index){
-		departureRoutes.remove(index);
+	public void delDepartureRoutes(int index) throws DataException{
+		if (departureRoutes.size() > index && index >= 0) {
+			departureRoutes.remove(index);
+		}else{
+			throw new DataException("Index "+index+" is out of number of Departure Routes array size.");
+		}
 	}
 
 	/**

src/main/java/seng202/group9/Core/City.java

@@ -1,5 +1,7 @@
 package seng202.group9.Core;
 
+import seng202.group9.Controller.DataException;
+
 import java.util.ArrayList;
 
 public class City {
@@ -137,9 +139,11 @@ public class City {
 	 * Deletes an Airport by Index from this City.
 	 * @param index
 	 */
-	public void delAirport(int index) {
-		if (airports.size() > index) {
+	public void delAirport(int index) throws DataException{
+		if (airports.size() > index && index >= 0) {
 			airports.remove(index);
+		}else{
+			throw new DataException("Index "+index+" is out of number of City Airports array size.");
 		}
 	}
 	@Override