Merge branch 'master' into fix-tools

# Conflicts:
#	pom.xml

config.yaml

@@ -319,6 +319,7 @@ server:
     NAME_CHANGE_COOLDOWN: 2592000000      # (30*24*60*60*1000) Cooldown for name changes, default (GMS) is 30 days.
     WORLD_TRANSFER_COOLDOWN: 2592000000  # (30*24*60*60*1000) Cooldown for world tranfers, default is same as name change (30 days).
     INSTANT_NAME_CHANGE: false              #Whether or not to wait for server restart to apply name changes. Does on reconnect otherwise (requires queries on every login).
+    REBIRTH_NPC_ID: 9010021                 #ID of the NPC that should be replaced with the rebirth mechanic, if enabled.
 
     #Dangling Items/Locks Configuration
     ITEM_EXPIRE_TIME: 180000    # (3 * 60 * 1000) Time before items start disappearing. Recommended to be set up to 3 minutes.
@@ -460,3 +461,7 @@ server:
     #Event End Timestamp
     EVENT_END_TIMESTAMP: 1428897600000
 
+    #Any NPC ids that should search for a js override script (useful if they already have wz entries since otherwise they're ignored).
+    NPCS_SCRIPTABLE:
+      #9200000: Talk to Cody # Cody
+      9001105: Rescue Gaga!  # Grandpa moon bunny

pom.xml

@@ -51,7 +51,11 @@
             <groupId>commons-io</groupId>
             <artifactId>commons-io</artifactId>
             <version>2.10.0</version>
-            <exclusions></exclusions>
+        </dependency>
+        <dependency>
+            <groupId>io.netty</groupId>
+            <artifactId>netty-buffer</artifactId>
+            <version>4.1.65.Final</version>
         </dependency>
 
         <!-- Logging -->
@@ -87,6 +91,20 @@
             <artifactId>js-scriptengine</artifactId>
             <version>${graalvm.version}</version>
         </dependency>
+
+        <!-- Testing -->
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-api</artifactId>
+            <version>5.7.2</version>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-engine</artifactId>
+            <version>5.7.2</version>
+        </dependency>
+
+
     </dependencies>
 
     <build>

scripts/npc/9010021.js

@@ -21,48 +21,9 @@
 */
 /* 9010021 - Wolf Spirit Ryko
     @author Ronan
- */
- var status;
-
+    @author wejrox
+*/
 function start() {
-    status = -1;
-    const YamlConfig = Java.type('config.YamlConfig');
-    if (!YamlConfig.config.server.USE_REBIRTH_SYSTEM) {
-        cm.sendOk("... I came from distant planes to assist the fight against the #rBlack Magician#k. Right now I search my master, have you seen him?");
-        cm.dispose();
-        return;
-    }
-    action(1, 0, 0);
-}
-
-function action(mode, type, selection) {
-    if (mode == 1) {
-        status++;
-    } else {
-        cm.dispose();
-        return;
-    }
-    if (status == 0) {
-        cm.sendNext("Come to me when you want to be reborn again. You currently have a total of #r" + cm.getChar().getReborns() + " #krebirths.");
-    } else if (status == 1) {
-        cm.sendSimple("What do you want me to do today: \r\n \r\n #L0##bI want to be rebirthed#l \r\n #L1##bMaybe next time#k#l");
-    } else if (status == 2) {
-        if (selection == 0) {
-            if (cm.getChar().getLevel() == 200) {
-                cm.sendYesNo("Are you sure you want to be rebirthed?");
-            } else {
-                cm.sendOk("You are not level 200, please come back when you hit level 200.");
-                cm.dispose();
-            }
-        } else if (selection == 1) {
-            cm.sendOk("Ok Bye")
-            cm.dispose();
-        }
-    } else if (status == 3 && type == 1) {
-        cm.getChar().executeReborn();
-        cm.sendOk("You have now been reborn. That's a total of #r" + cm.getChar().getReborns() + "#k rebirths");
-        cm.dispose();
-    }
-
-
+    cm.sendOk("... I came from distant planes to assist the fight against the #rBlack Magician#k. Right now I search my master, have you seen him?");
+    cm.dispose();
 }

scripts/npc/rebirth.js

@@ -0,0 +1,67 @@
+/*
+	This file is part of the OdinMS Maple Story Server
+    Copyright (C) 2008 Patrick Huy <patrick.huy@frz.cc>
+		       Matthias Butz <matze@odinms.de>
+		       Jan Christian Meyer <vimes@odinms.de>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as
+    published by the Free Software Foundation version 3 as published by
+    the Free Software Foundation. You may not use, modify or distribute
+    this program under any other version of the GNU Affero General Public
+    License.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/* Rebirth NPC
+    @author Ronan
+    @author wejrox
+*/
+var status;
+
+function start() {
+    status = -1;
+    const YamlConfig = Java.type('config.YamlConfig');
+    if (!YamlConfig.config.server.USE_REBIRTH_SYSTEM) {
+        cm.sendOk("Rebirths aren't enabled on this server, how did you get here?");
+        cm.dispose();
+        return;
+    }
+    action(1, 0, 0);
+}
+
+function action(mode, type, selection) {
+    if (mode === 1) {
+        status++;
+    } else {
+        cm.dispose();
+        return;
+    }
+    if (status === 0) {
+        cm.sendNext("Come to me when you want to be reborn again. You currently have a total of #r" + cm.getChar().getReborns() + " #krebirths.");
+    } else if (status === 1) {
+        cm.sendSimple("What do you want me to do today: \r\n \r\n #L0##bI want to be reborn!#l \r\n #L1##bNothing for now...#k#l");
+    } else if (status === 2) {
+        if (selection === 0) {
+            if (cm.getChar().getLevel() === 200) {
+                cm.sendYesNo("Are you sure you want to be reborn?");
+            } else {
+                cm.sendOk("You are not level 200, please come back when you hit level 200.");
+                cm.dispose();
+            }
+        } else if (selection === 1) {
+            cm.sendOk("See you soon!")
+            cm.dispose();
+        }
+    } else if (status === 3 && type === 1) {
+        cm.getChar().executeReborn();
+        cm.sendOk("You have now been reborn. That's a total of #r" + cm.getChar().getReborns() + "#k rebirths");
+        cm.dispose();
+    }
+}

src/main/java/config/ServerConfig.java

@@ -1,5 +1,7 @@
 package config;
 
+import java.util.*;
+
 public class ServerConfig {
     //Thread Tracker Configuration
     public boolean USE_THREAD_TRACKER;
@@ -163,6 +165,7 @@ public class ServerConfig {
     public long NAME_CHANGE_COOLDOWN;
     public long WORLD_TRANSFER_COOLDOWN=NAME_CHANGE_COOLDOWN;//Cooldown for world tranfers, default is same as name change (30 days).
     public boolean INSTANT_NAME_CHANGE;
+    public int REBIRTH_NPC_ID;
 
     //Dangling Items/Locks Configuration
     public int ITEM_EXPIRE_TIME ;
@@ -304,4 +307,6 @@ public class ServerConfig {
     //Event End Timestamp
     public long EVENT_END_TIMESTAMP;
 
+    //Custom NPC overrides. List of NPC IDs.
+    public Map<String, String> NPCS_SCRIPTABLE = new HashMap<>();
 }

src/main/java/constants/game/ScriptableNPCConstants.java

@@ -1,24 +0,0 @@
-package constants.game;
- 
-/**
- * @brief ScriptableNPCConstants
- * @author GabrielSin <gabrielsin@playellin.net>
- * @date   16/09/2018
- * 
- * Adaptations to use Pair and Set, in order to suit a one-packet marshall.
- * Adapted by Ronan
- */
-
-import java.util.HashSet;
-import java.util.Set;
-import tools.Pair;
-
-public class ScriptableNPCConstants {
-    
-    public static final Set<Pair<Integer, String>> SCRIPTABLE_NPCS = new HashSet<Pair<Integer, String>>(){{
-        //add(new Pair<>(9200000, "Cody"));
-        add(new Pair<>(9001105, "Grandpa Moon Bunny"));
-    }};
-    
-}
- 

src/main/java/net/packet/ByteBufInPacket.java

@@ -0,0 +1,81 @@
+package net.packet;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufUtil;
+
+import java.awt.*;
+
+public class ByteBufInPacket implements InPacket {
+    private final ByteBuf byteBuf;
+
+    public ByteBufInPacket(ByteBuf byteBuf) {
+        this.byteBuf = byteBuf;
+    }
+
+    @Override
+    public byte[] getBytes() {
+        return ByteBufUtil.getBytes(byteBuf);
+    }
+
+    @Override
+    public byte readByte() {
+        return byteBuf.readByte();
+    }
+
+    @Override
+    public short readShort() {
+        return byteBuf.readShortLE();
+    }
+
+    @Override
+    public int readInt() {
+        return byteBuf.readIntLE();
+    }
+
+    @Override
+    public long readLong() {
+        return byteBuf.readLongLE();
+    }
+
+    @Override
+    public Point readPoint() {
+        final short x = byteBuf.readShortLE();
+        final short y = byteBuf.readShortLE();
+        return new Point(x, y);
+    }
+
+    @Override
+    public String readString() {
+        short length = readShort();
+        byte[] stringBytes = new byte[length];
+        byteBuf.readBytes(stringBytes);
+        return new String(stringBytes, STRING_CHARSET);
+    }
+
+    @Override
+    public byte[] readBytes(int numberOfBytes) {
+        byte[] bytes = new byte[numberOfBytes];
+        byteBuf.readBytes(bytes);
+        return bytes;
+    }
+
+    @Override
+    public void skip(int numberOfBytes) {
+        byteBuf.skipBytes(numberOfBytes);
+    }
+
+    @Override
+    public int available() {
+        return byteBuf.readableBytes();
+    }
+
+    @Override
+    public void seek(int byteOffset) {
+        byteBuf.readerIndex(byteOffset);
+    }
+
+    @Override
+    public int getPosition() {
+        return byteBuf.readerIndex();
+    }
+}

src/main/java/net/packet/ByteBufOutPacket.java

@@ -0,0 +1,83 @@
+package net.packet;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufUtil;
+import io.netty.buffer.Unpooled;
+import net.jcip.annotations.NotThreadSafe;
+import net.opcodes.SendOpcode;
+
+import java.awt.*;
+
+@NotThreadSafe
+public class ByteBufOutPacket implements OutPacket {
+    private final ByteBuf byteBuf;
+
+    public ByteBufOutPacket(SendOpcode op) {
+        ByteBuf byteBuf = Unpooled.buffer();
+        byteBuf.writeShortLE((short) op.getValue());
+        this.byteBuf = byteBuf;
+    }
+
+    public ByteBufOutPacket(SendOpcode op, int initialCapacity) {
+        ByteBuf byteBuf = Unpooled.buffer(initialCapacity);
+        byteBuf.writeShortLE((short) op.getValue());
+        this.byteBuf = byteBuf;
+    }
+
+    @Override
+    public byte[] getBytes() {
+        return ByteBufUtil.getBytes(byteBuf);
+    }
+
+    @Override
+    public void writeByte(byte value) {
+        byteBuf.writeByte(value);
+    }
+
+    @Override
+    public void writeByte(int value) {
+        writeByte((byte) value);
+    }
+
+    @Override
+    public void writeBytes(byte[] value) {
+        byteBuf.writeBytes(value);
+    }
+
+    @Override
+    public void writeShort(int value) {
+        byteBuf.writeShortLE(value);
+    }
+
+    @Override
+    public void writeInt(int value) {
+        byteBuf.writeIntLE(value);
+    }
+
+    @Override
+    public void writeLong(long value) {
+        byteBuf.writeLongLE(value);
+    }
+
+    @Override
+    public void writeBoolean(boolean value) {
+        byteBuf.writeByte(value ? 1 : 0);
+    }
+
+    @Override
+    public void writeString(String value) {
+        writeShort((short) value.length());
+        writeBytes(value.getBytes(STRING_CHARSET));
+    }
+
+    @Override
+    public void writePoint(Point value) {
+        writeShort((short) value.getX());
+        writeShort((short) value.getY());
+    }
+
+    @Override
+    public void skip(int numberOfBytes) {
+        writeBytes(new byte[numberOfBytes]);
+    }
+}

src/main/java/net/packet/InPacket.java

@@ -0,0 +1,17 @@
+package net.packet;
+
+import java.awt.*;
+
+public interface InPacket extends Packet {
+    byte readByte();
+    short readShort();
+    int readInt();
+    long readLong();
+    Point readPoint();
+    String readString();
+    byte[] readBytes(int numberOfBytes);
+    void skip(int numberOfBytes);
+    int available();
+    void seek(int byteOffset);
+    int getPosition();
+}

src/main/java/net/packet/OutPacket.java

@@ -0,0 +1,16 @@
+package net.packet;
+
+import java.awt.*;
+
+public interface OutPacket extends Packet {
+    void writeByte(byte value);
+    void writeByte(int value);
+    void writeBytes(byte[] value);
+    void writeShort(int value);
+    void writeInt(int value);
+    void writeLong(long value);
+    void writeBoolean(boolean value);
+    void writeString(String value);
+    void writePoint(Point value);
+    void skip(int numberOfBytes);
+}

src/main/java/net/packet/Packet.java

@@ -0,0 +1,10 @@
+package net.packet;
+
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+
+public interface Packet {
+    Charset STRING_CHARSET = StandardCharsets.US_ASCII;
+
+    byte[] getBytes();
+}

src/main/java/net/server/channel/handlers/NPCTalkHandler.java

@@ -65,6 +65,8 @@ public final class NPCTalkHandler extends AbstractMaplePacketHandler {
                     NPCScriptManager.getInstance().start(c, npc.getId(), "gachapon", null);
                 } else if (npc.getName().endsWith("Maple TV")) {
                     NPCScriptManager.getInstance().start(c, npc.getId(), "mapleTV", null);
+                } else if (YamlConfig.config.server.USE_REBIRTH_SYSTEM && npc.getId() == YamlConfig.config.server.REBIRTH_NPC_ID) {
+                    NPCScriptManager.getInstance().start(c, npc.getId(), "rebirth", null);
                 } else {
                     boolean hasNpcScript = NPCScriptManager.getInstance().start(c, npc.getId(), oid, null);
                     if (!hasNpcScript) {

src/main/java/net/server/channel/handlers/PlayerLoggedinHandler.java

@@ -26,7 +26,6 @@ import client.inventory.*;
 import client.keybind.MapleKeyBinding;
 import config.YamlConfig;
 import constants.game.GameConstants;
-import constants.game.ScriptableNPCConstants;
 import net.AbstractMaplePacketHandler;
 import net.server.PlayerBuffValueHolder;
 import net.server.Server;
@@ -55,6 +54,7 @@ import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.*;
 import java.util.Map.Entry;
+import java.util.stream.Collectors;
 
 public final class PlayerLoggedinHandler extends AbstractMaplePacketHandler {
 
@@ -407,9 +407,23 @@ public final class PlayerLoggedinHandler extends AbstractMaplePacketHandler {
                         eim.registerPlayer(player);
                     }
                 }
-                
+
+                // Tell the client to use the custom scripts available for the NPCs provided, instead of the WZ entries.
                 if (YamlConfig.config.server.USE_NPCS_SCRIPTABLE) {
-                    c.announce(MaplePacketCreator.setNPCScriptable(ScriptableNPCConstants.SCRIPTABLE_NPCS));
+
+                    // Create a copy to prevent always adding entries to the server's list.
+                    Map<Integer, String> npcsIds = YamlConfig.config.server.NPCS_SCRIPTABLE
+                            .entrySet().stream().collect(Collectors.toMap(
+                                    entry -> Integer.parseInt(entry.getKey()),
+                                    Entry::getValue
+                            ));
+
+                    // Any npc be specified as the rebirth npc. Allow the npc to use custom scripts explicitly.
+                    if (YamlConfig.config.server.USE_REBIRTH_SYSTEM) {
+                        npcsIds.put(YamlConfig.config.server.REBIRTH_NPC_ID, "Rebirth");
+                    }
+
+                    c.announce(MaplePacketCreator.setNPCScriptable(npcsIds));
                 }
                 
                 if(newcomer) player.setLoginTime(System.currentTimeMillis());

src/main/java/tools/MaplePacketCreator.java

@@ -8327,17 +8327,25 @@ public class MaplePacketCreator {
                 mplew.writeInt(transition);
                 return mplew.getPacket();
         }
-        
-        public static byte[] setNPCScriptable(Set<Pair<Integer, String>> scriptNpcDescriptions) {  // thanks to GabrielSin
+
+        /**
+         * Makes the NPCs provided set as scriptable, informing the client to search for js scripts for these NPCs even
+         * if they already have entries within the wz files.
+         *
+         * @param scriptableNpcIds Ids of npcs to enable scripts for.
+         * @return a packet which makes the npc's provided scriptable.
+         */
+        public static byte[] setNPCScriptable(Map<Integer, String> scriptableNpcIds) {  // thanks to GabrielSin
                 MaplePacketLittleEndianWriter mplew = new MaplePacketLittleEndianWriter();
                 mplew.writeShort(SendOpcode.SET_NPC_SCRIPTABLE.getValue());
-                mplew.write(scriptNpcDescriptions.size());
-                for (Pair<Integer, String> p : scriptNpcDescriptions) {
-                        mplew.writeInt(p.getLeft());
-                        mplew.writeMapleAsciiString(p.getRight());
+                mplew.write(scriptableNpcIds.size());
+                scriptableNpcIds.forEach((id, name) -> {
+                        mplew.writeInt(id);
+                        // The client needs a name for the npc conversation, which is displayed under etc when the npc has a quest available.
+                        mplew.writeMapleAsciiString(name);
                         mplew.writeInt(0); // start time
                         mplew.writeInt(Integer.MAX_VALUE); // end time
-                }
+                });
                 return mplew.getPacket();
         }
         
@@ -8383,17 +8391,17 @@ public class MaplePacketCreator {
                 final MaplePacketLittleEndianWriter mplew = new MaplePacketLittleEndianWriter();
                 mplew.writeShort(SendOpcode.TOURNAMENT_SET_PRIZE.getValue());
 				
-		//0 = "You have failed the set the prize. Please check the item number again."
-		//1 = "You have successfully set the prize."
-		mplew.write(bSetPrize);
-		
-		mplew.write(bHasPrize);
-		
-		if(bHasPrize != 0)
-		{
-			mplew.writeInt(nItemID1);
-			mplew.writeInt(nItemID2);
-		}
+                //0 = "You have failed the set the prize. Please check the item number again."
+                //1 = "You have successfully set the prize."
+                mplew.write(bSetPrize);
+
+                mplew.write(bHasPrize);
+
+                if(bHasPrize != 0)
+                {
+                    mplew.writeInt(nItemID1);
+                    mplew.writeInt(nItemID2);
+                }
 		
                 return mplew.getPacket();
         }
@@ -8402,11 +8410,11 @@ public class MaplePacketCreator {
                 final MaplePacketLittleEndianWriter mplew = new MaplePacketLittleEndianWriter();
                 mplew.writeShort(SendOpcode.TOURNAMENT_UEW.getValue());
 				
-		//Is this a bitflag o.o ?
-		//2 = "You have reached the finals by default."
-		//4 = "You have reached the semifinals by default."
-		//8 or 16 = "You have reached the round of %n by default." | Encodes nState as %n ?!
-		mplew.write(nState);
+                //Is this a bitflag o.o ?
+                //2 = "You have reached the finals by default."
+                //4 = "You have reached the semifinals by default."
+                //8 or 16 = "You have reached the round of %n by default." | Encodes nState as %n ?!
+                mplew.write(nState);
 			
                 return mplew.getPacket();
         }

src/test/java/net/packet/ByteBufInPacketTest.java

@@ -0,0 +1,192 @@
+package net.packet;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.awt.*;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class ByteBufInPacketTest {
+    private ByteBuf byteBuf;
+    private InPacket inPacket;
+
+    @BeforeEach
+    void reset() {
+        this.byteBuf = Unpooled.buffer();
+        this.inPacket = new ByteBufInPacket(byteBuf);
+    }
+
+    private void givenWrittenBytes(int... bytes) {
+        for (int b : bytes) {
+            byteBuf.writeByte(b);
+        }
+    }
+
+    @Test
+    void readByte() {
+        final byte writtenByte = 123;
+        byteBuf.writeByte(writtenByte);
+
+        byte readByte = inPacket.readByte();
+
+        assertEquals(writtenByte, readByte);
+    }
+
+    @Test
+    void readShort() {
+        final short writtenShort = 12_345;
+        byteBuf.writeShortLE(writtenShort);
+
+        short readShort = inPacket.readShort();
+
+        assertEquals(writtenShort, readShort);
+    }
+
+    @Test
+    void readInt() {
+        final int writtenInt = 1_234_567_890;
+        byteBuf.writeIntLE(writtenInt);
+
+        int readInt = inPacket.readInt();
+
+        assertEquals(writtenInt, readInt);
+    }
+
+    @Test
+    void readLong() {
+        final long writtenLong = 9_223_372_036_854_775_807L;
+        byteBuf.writeLongLE(writtenLong);
+
+        long readLong = inPacket.readLong();
+
+        assertEquals(writtenLong, readLong);
+    }
+
+    @Test
+    void readPoint() {
+        final Point writtenPoint = new Point(111, 222);
+        byteBuf.writeShortLE((short) writtenPoint.getX());
+        byteBuf.writeShortLE((short) writtenPoint.getY());
+
+        Point readPoint = inPacket.readPoint();
+
+        assertEquals(writtenPoint, readPoint);
+    }
+
+    @Test
+    void readString() {
+        final String writtenString = "You have gained experience (+3200)";
+        byteBuf.writeShortLE(writtenString.length());
+        byte[] writtenStringBytes = writtenString.getBytes(Packet.STRING_CHARSET);
+        byteBuf.writeBytes(writtenStringBytes);
+
+        String readString = inPacket.readString();
+
+        assertEquals(writtenString, readString);
+    }
+
+    @Test
+    void readBytes() {
+        givenWrittenBytes(10, 11, 12, 13, 14, 15);
+
+        byte[] byteBatch1 = inPacket.readBytes(1);
+        assertEquals(1, byteBatch1.length);
+        assertEquals(10, byteBatch1[0]);
+
+        byte[] byteBatch2 = inPacket.readBytes(2);
+        assertEquals(2, byteBatch2.length);
+        assertEquals(11, byteBatch2[0]);
+        assertEquals(12, byteBatch2[1]);
+
+        byte[] byteBatch3 = inPacket.readBytes(3);
+        assertEquals(3, byteBatch3.length);
+        assertEquals(13, byteBatch3[0]);
+        assertEquals(14, byteBatch3[1]);
+        assertEquals(15, byteBatch3[2]);
+    }
+
+    @Test
+    void skip() {
+        givenWrittenBytes(20, 21, 22, 23, 24, 25);
+
+        byte firstByte = inPacket.readByte();
+        assertEquals(20, firstByte);
+
+        inPacket.skip(3);
+
+        byte fifthByte = inPacket.readByte();
+        assertEquals(24, fifthByte);
+    }
+
+    @Test
+    void available() {
+        givenWrittenBytes(30, 31, 32, 33, 34, 35);
+
+        assertEquals(6, inPacket.available());
+
+        inPacket.readByte();
+        assertEquals(5, inPacket.available());
+
+        inPacket.readInt();
+        assertEquals(1, inPacket.available());
+    }
+
+    @Test
+    void seek() {
+        givenWrittenBytes(40, 41, 42, 43, 44, 45);
+
+        inPacket.seek(2);
+        assertEquals(4, inPacket.available());
+        byte byteAtSeek = inPacket.readByte();
+        assertEquals(42, byteAtSeek);
+
+        inPacket.seek(0);
+        byte byteAtReset = inPacket.readByte();
+        assertEquals(40, byteAtReset);
+    }
+
+    @Test
+    void getPosition() {
+        givenWrittenBytes(50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60);
+
+        assertEquals(0, inPacket.getPosition());
+
+        inPacket.readByte();
+        assertEquals(1, inPacket.getPosition());
+
+        inPacket.readShort();
+        assertEquals(3, inPacket.getPosition());
+
+        inPacket.readInt();
+        assertEquals(7, inPacket.getPosition());
+
+        inPacket.seek(5);
+        assertEquals(5, inPacket.getPosition());
+    }
+
+    @Test
+    void getBytes() {
+        givenWrittenBytes(20, 19, 21, 18, 22);
+
+        byte[] bytes = inPacket.getBytes();
+
+        assertArrayEquals(new byte[]{20, 19, 21, 18, 22}, bytes);
+    }
+
+    @Test
+    void whenGetBytes_shouldBeRepeatable() {
+        givenWrittenBytes(1, 2, 3, 4, 5);
+
+        byte[] bytes = inPacket.getBytes();
+        assertEquals(5, bytes.length);
+
+        byte[] sameBytes = inPacket.getBytes();
+        assertEquals(5, sameBytes.length);
+
+        assertArrayEquals(bytes, sameBytes);
+    }
+}

src/test/java/net/packet/ByteBufOutPacketTest.java

@@ -0,0 +1,206 @@
+package net.packet;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import net.opcodes.SendOpcode;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.awt.*;
+import java.nio.charset.StandardCharsets;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class ByteBufOutPacketTest {
+    private ByteBufOutPacket outPacket;
+
+    @BeforeEach
+    void reset() {
+        outPacket = new ByteBufOutPacket(SendOpcode.ADMIN_SHOP); // Any opcode will do
+    }
+
+    private static ByteBuf wrapExplicitlyWrittenBytes(OutPacket outPacket) {
+        byte[] packetBytes = outPacket.getBytes();
+        ByteBuf byteBuf = Unpooled.copiedBuffer(packetBytes);
+        byteBuf.readShortLE(); // Skip over opcode
+        return byteBuf;
+    }
+
+    @Test
+    void whenInstantiatingNew_shouldWriteOpcode() {
+        byte[] packetBytes = new ByteBufOutPacket(SendOpcode.NPC_TALK).getBytes();
+        assertEquals(2, packetBytes.length);
+    }
+
+    @Test
+    void getBytes() {
+        ByteBufOutPacket outPacket = new ByteBufOutPacket(SendOpcode.PING); // This opcode has value 0x11 = 17 in decimal
+        outPacket.writeByte(10);
+        outPacket.writeByte(20);
+        outPacket.writeByte(30);
+
+        byte[] bytes = outPacket.getBytes();
+
+        assertArrayEquals(new byte[]{(byte) 17, (byte) 0, (byte) 10, (byte) 20, (byte) 30}, bytes);
+    }
+
+    @Test
+    void writeByte() {
+        final byte writtenByte = 19;
+        outPacket.writeByte(writtenByte);
+
+        ByteBuf wrapped = wrapExplicitlyWrittenBytes(outPacket);
+        byte readByte = wrapped.readByte();
+
+        assertEquals(writtenByte, readByte);
+    }
+
+    @Test
+    void writeByteFromInt() {
+        final int writtenInt = 123;
+        outPacket.writeByte(writtenInt);
+
+        ByteBuf wrapped = wrapExplicitlyWrittenBytes(outPacket);
+        byte readByte = wrapped.readByte();
+
+        assertEquals(writtenInt, readByte);
+    }
+
+    @Test
+    void whenWritingByteFromInt_shouldOnlyWrite1Byte() {
+        final int writtenInt = Integer.MAX_VALUE;
+        outPacket.writeByte(writtenInt);
+
+        byte[] bytes = outPacket.getBytes();
+        assertEquals(2 + 1, bytes.length); // 2 for opcode
+    }
+
+    @Test
+    void writeBytes() {
+        byte[] writtenBytes = {101, 102, 103};
+        outPacket.writeBytes(writtenBytes);
+
+        ByteBuf wrapped = wrapExplicitlyWrittenBytes(outPacket);
+
+        assertEquals(101, wrapped.readByte());
+        assertEquals(102, wrapped.readByte());
+        assertEquals(103, wrapped.readByte());
+    }
+
+    @Test
+    void writeShort() {
+        final short writtenShort = 4312;
+        outPacket.writeShort(writtenShort);
+
+        ByteBuf wrapped = wrapExplicitlyWrittenBytes(outPacket);
+        short readShort = wrapped.readShortLE();
+
+        assertEquals(writtenShort, readShort);
+    }
+
+    @Test
+    void whenWritingShortFromInt_shouldOnlyWrite2Bytes() {
+        final int writtenInt = Integer.MAX_VALUE;
+        outPacket.writeShort(writtenInt);
+
+        byte[] bytes = outPacket.getBytes();
+        assertEquals(2 + 2, bytes.length); // 2 for opcode
+    }
+
+    @Test
+    void writeShortFromInt() {
+        final int writtenInt = 34_567;
+        outPacket.writeShort(writtenInt);
+
+        ByteBuf wrapped = wrapExplicitlyWrittenBytes(outPacket);
+        short readShort = wrapped.readShortLE();
+
+        assertEquals((short) writtenInt, readShort);
+    }
+
+    @Test
+    void writeInt() {
+        final int writtenInt = 1_010_101_010;
+        outPacket.writeInt(writtenInt);
+
+        ByteBuf wrapped = wrapExplicitlyWrittenBytes(outPacket);
+        int readInt = wrapped.readIntLE();
+
+        assertEquals(writtenInt, readInt);
+    }
+
+    @Test
+    void writeLong() {
+        final long writtenLong = 100_200_300_400_500_600L;
+        outPacket.writeLong(writtenLong);
+
+        ByteBuf wrapped = wrapExplicitlyWrittenBytes(outPacket);
+        long readLong = wrapped.readLongLE();
+
+        assertEquals(writtenLong, readLong);
+    }
+
+    @Test
+    void writeBoolean_true() {
+        outPacket.writeBoolean(true);
+
+        ByteBuf wrapped = wrapExplicitlyWrittenBytes(outPacket);
+        byte readByte = wrapped.readByte();
+
+        assertEquals(1, readByte);
+    }
+
+    @Test
+    void writeBoolean_false() {
+        outPacket.writeBoolean(false);
+
+        ByteBuf wrapped = wrapExplicitlyWrittenBytes(outPacket);
+        byte readByte = wrapped.readByte();
+
+        assertEquals(0, readByte);
+    }
+
+    @Test
+    void writeString() {
+        final String writtenString = "You've been weakened, making you unable to jump.";
+        outPacket.writeString(writtenString);
+
+        ByteBuf wrapped = wrapExplicitlyWrittenBytes(outPacket);
+        int length = wrapped.readShortLE();
+        byte[] stringBytes = new byte[length];
+        wrapped.readBytes(stringBytes);
+        String readString = new String(stringBytes, StandardCharsets.US_ASCII);
+
+        assertEquals(writtenString, readString);
+    }
+
+    @Test
+    void writePoint() {
+        final Point writtenPoint = new Point(23, 42);
+        outPacket.writePoint(writtenPoint);
+
+        ByteBuf wrapped = wrapExplicitlyWrittenBytes(outPacket);
+        short readX = wrapped.readShortLE();
+        short readY = wrapped.readShortLE();
+
+        assertEquals((short) writtenPoint.getX(), readX);
+        assertEquals((short) writtenPoint.getY(), readY);
+    }
+
+    @Test
+    void whenSkipping_shouldWriteZeroes() {
+        final byte firstWrittenByte = 9;
+        final byte secondWrittenByte = 11;
+        outPacket.writeByte(firstWrittenByte);
+        outPacket.skip(2);
+        outPacket.writeByte(secondWrittenByte);
+
+        ByteBuf wrapped = wrapExplicitlyWrittenBytes(outPacket);
+
+        assertEquals(firstWrittenByte, wrapped.readByte());
+        assertEquals(0, wrapped.readByte());
+        assertEquals(0, wrapped.readByte());
+        assertEquals(secondWrittenByte, wrapped.readByte());
+    }
+}