Update region cost computation

pom.xml

@@ -57,6 +57,11 @@
 			<version>4.10</version>
 			<scope>test</scope>
 		</dependency>
+		<dependency>
+			<groupId>org.mockito</groupId>
+			<artifactId>mockito-core</artifactId>
+			<version>3.12.4</version>
+		</dependency>
 	</dependencies>
 	<build>
     <extensions>

src/main/java/us/camin/regions/Region.java

@@ -148,23 +148,43 @@ public void addCharges(int charges) {
       m_charges += charges;
     }
 
+    /**
+     * Travel should cost:
+     * <ul>
+     * <li>0 XP levels between hubs</li>
+     * <li>1 XP level if the player is leaving a hub</li>
+     * <li>A scaling amount of XP for the rest, halved if the destination is a hub.</li>
+     * </ul>
+     * @param destination	The region the player is traveling to
+     * @return				The amount of XP to deduct from the player
+     */
     public int getTravelCost(Region destination) {
+      if (isHub() && destination.isHub()) {
+         return 0;
+      } else if (isHub()) {
+    	  return 1;
+      }
       int baseCost = getBaseTravelCost(destination);
+      if (baseCost == 0) {
+    	  return baseCost;
+      }
       if (destination.isHub()) {
           // Travel *to* a hub is 50% cheaper, before charges applied
           baseCost /= 2;
       }
-      return Math.max(1, (int)(baseCost / (Math.min(4, m_charges + 1))));
+      return Math.max(1, (int)(baseCost / (Math.min(4, charges() + 1))));
     }
 
+    /**
+     * Computes the raw cost to teleport between two regions, in XP levels.
+     * 
+     * NOTE: This computation does not include any discounts for hub-based transit,
+     * nor does it compute any charge-based discounts.
+     * 
+     * @param destination	The region being traveled to
+     * @return				The base cost in XP levels to travel to the given region without any discounts applied
+     */
     public int getBaseTravelCost(Region destination) {
-      if (m_isHub && destination.isHub()) {
-        // Free travel between hubs
-        return 0;
-      } else if (m_isHub) {
-        // Max cost 1 level for travel *from* a hub
-        return 1;
-      }
       double distance = teleportLocation().distance(destination.teleportLocation());
       double blocksPerXP = 500;
       return Math.max(1, (int)(distance / blocksPerXP));

src/test/java/us/camin/regions/RegionTest.java

@@ -0,0 +1,77 @@
+package us.camin.regions;
+
+import static org.junit.Assert.*;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.bukkit.World;
+import org.junit.Test;
+import org.mockito.Mockito;
+
+import us.camin.regions.config.RegionConfiguration;
+
+public class RegionTest {
+
+	private World world = Mockito.mock(World.class);
+
+	@Test
+	public void testHubToHubCost() {
+		Map<String, Object> cfg = buildBaseConfig();
+		cfg.put("isHub", true);
+
+		Region r1 = new Region("R1", world, new RegionConfiguration(cfg));
+
+		cfg.put("x", 1000);
+		Region r2 = new Region("R2", world, new RegionConfiguration(cfg));
+
+		assertEquals("hub to hub travel cost should be zero", 0, r1.getTravelCost(r2));
+	}
+
+	@Test
+	public void testHubDestinationCost() {
+		Map<String, Object> cfg = buildBaseConfig();
+		cfg.put("isHub", true);
+
+		Region hub = new Region("hub", world, new RegionConfiguration(cfg));
+
+		cfg.put("isHub", false);
+		cfg.put("x", 1000);
+		Region region = new Region("region", world, new RegionConfiguration(cfg));
+
+		assertEquals("Traveling to a hub should be half as expensive", 1, region.getTravelCost(hub));
+	}
+
+	@Test
+	public void testHubSourceCost() {
+		Map<String, Object> cfg = buildBaseConfig();
+		cfg.put("isHub", true);
+
+		Region hub = new Region("hub", world, new RegionConfiguration(cfg));
+
+		cfg.put("isHub", false);
+		cfg.put("x", 1000);
+		Region region = new Region("region", world, new RegionConfiguration(cfg));
+
+		assertEquals("leaving a hub should always cost 1", 1, hub.getTravelCost(region));
+	}
+
+	@Test
+	public void testRegionCost() {
+		Map<String, Object> cfg = buildBaseConfig();
+
+		Region r1 = new Region("r1", world, new RegionConfiguration(cfg));
+		cfg.put("x", 1000);
+		Region r2 = new Region("r2", world, new RegionConfiguration(cfg));
+
+		assertEquals("travel cost should be 1xp per 500 blocks", 2, r1.getTravelCost(r2));
+	}
+
+	private static Map<String, Object> buildBaseConfig() {
+		Map<String, Object> cfg = new HashMap<>();
+		cfg.put("x", 0);
+		cfg.put("y", 0);
+		cfg.put("z", 0);
+		return cfg;
+	}
+}