xptracker: fix calculating xp offset from offline xp

runelite-client/src/main/java/net/runelite/client/plugins/xptracker/XpTrackerPlugin.java

@@ -25,6 +25,7 @@
  */
 package net.runelite.client.plugins.xptracker;
 
+import com.google.common.annotations.VisibleForTesting;
 import static com.google.common.base.MoreObjects.firstNonNull;
 import com.google.common.collect.ImmutableList;
 import com.google.inject.Binder;
@@ -36,6 +37,8 @@ import java.util.EnumSet;
 import java.util.List;
 import java.util.Objects;
 import javax.inject.Inject;
+import lombok.AccessLevel;
+import lombok.Setter;
 import lombok.extern.slf4j.Slf4j;
 import net.runelite.api.Actor;
 import net.runelite.api.Client;
@@ -114,6 +117,8 @@ public class XpTrackerPlugin extends Plugin
 	private OverlayManager overlayManager;
 
 	private NavigationButton navButton;
+	@Setter(AccessLevel.PACKAGE)
+	@VisibleForTesting
 	private XpPanel xpPanel;
 	private XpWorldType lastWorldType;
 	private String lastUsername;
@@ -412,7 +417,7 @@ public class XpTrackerPlugin extends Plugin
 
 					log.debug("Skill xp for {} changed when offline: {} -> {}", skill, skillState.getCurrentXp(), currentXp);
 					// Offset start xp for offline gains
-					long diff = skillState.getCurrentXp() - currentXp;
+					long diff = currentXp - skillState.getCurrentXp();
 					skillState.setStartXp(skillState.getStartXp() + diff);
 				}
 			}
@@ -512,6 +517,11 @@ public class XpTrackerPlugin extends Plugin
 		}
 	}
 
+	XpStateSingle getSkillState(Skill skill)
+	{
+		return xpState.getSkill(skill);
+	}
+
 	XpSnapshotSingle getSkillSnapshot(Skill skill)
 	{
 		return xpState.getSkillSnapshot(skill);

runelite-client/src/test/java/net/runelite/client/plugins/xptracker/XpTrackerPluginTest.java

@@ -0,0 +1,123 @@
+/*
+ * Copyright (c) 2019, Adam <Adam@sigterm.info>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package net.runelite.client.plugins.xptracker;
+
+import com.google.inject.Guice;
+import com.google.inject.testing.fieldbinder.Bind;
+import com.google.inject.testing.fieldbinder.BoundFieldModule;
+import java.util.EnumSet;
+import javax.inject.Inject;
+import net.runelite.api.Client;
+import net.runelite.api.GameState;
+import net.runelite.api.Player;
+import net.runelite.api.Skill;
+import net.runelite.api.WorldType;
+import net.runelite.api.events.ExperienceChanged;
+import net.runelite.api.events.GameStateChanged;
+import net.runelite.api.events.GameTick;
+import net.runelite.client.game.NPCManager;
+import net.runelite.client.game.SkillIconManager;
+import net.runelite.client.ui.ClientToolbar;
+import net.runelite.client.ui.overlay.OverlayManager;
+import static org.junit.Assert.assertEquals;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+import org.mockito.runners.MockitoJUnitRunner;
+
+@RunWith(MockitoJUnitRunner.class)
+public class XpTrackerPluginTest
+{
+	@Inject
+	private XpTrackerPlugin xpTrackerPlugin;
+
+	@Mock
+	@Bind
+	private ClientToolbar clientToolbar;
+
+	@Mock
+	@Bind
+	private Client client;
+
+	@Mock
+	@Bind
+	private SkillIconManager skillIconManager;
+
+	@Mock
+	@Bind
+	private XpTrackerConfig xpTrackerConfig;
+
+	@Mock
+	@Bind
+	private NPCManager npcManager;
+
+	@Mock
+	@Bind
+	private OverlayManager overlayManager;
+
+	@Before
+	public void before()
+	{
+		Guice.createInjector(BoundFieldModule.of(this)).injectMembers(this);
+
+		when(client.getWorldType()).thenReturn(EnumSet.of(WorldType.MEMBERS));
+		when(client.getLocalPlayer()).thenReturn(mock(Player.class));
+
+		xpTrackerPlugin.setXpPanel(mock(XpPanel.class));
+	}
+
+	@Test
+	public void testOfflineXp()
+	{
+		GameStateChanged gameStateChanged = new GameStateChanged();
+		gameStateChanged.setGameState(GameState.LOGGING_IN);
+
+		// Flag initialization of tracker
+		xpTrackerPlugin.onGameStateChanged(gameStateChanged);
+		when(client.getSkillExperience(Skill.ATTACK)).thenReturn(42);
+		// Initialize tracker
+		xpTrackerPlugin.onGameTick(new GameTick());
+
+		// Gain attack xp
+		when(client.getSkillExperience(Skill.ATTACK)).thenReturn(100);
+		ExperienceChanged experienceChanged = new ExperienceChanged();
+		experienceChanged.setSkill(Skill.ATTACK);
+		xpTrackerPlugin.onExperienceChanged(experienceChanged);
+
+		// Offline gain
+		when(client.getSkillExperience(Skill.ATTACK)).thenReturn(42000);
+		// Flag initialization of tracker
+		xpTrackerPlugin.onGameStateChanged(gameStateChanged);
+		// Initialize tracker
+		xpTrackerPlugin.onGameTick(new GameTick());
+
+		// Start at 42 xp, gain of 58 xp, offline gain of 41900 xp - offset start XP: 42 + 41900
+		XpStateSingle skillState = xpTrackerPlugin.getSkillState(Skill.ATTACK);
+		assertEquals(41942, skillState.getStartXp());
+	}
+}