Convert into a multi-module project.

For now, the API module only contains a few assorted utilities. More
will be added later.

proxy/src/test/java/com/velocitypowered/proxy/protocol/PacketRegistryTest.java

@@ -0,0 +1,53 @@
+package com.velocitypowered.proxy.protocol;
+
+import com.velocitypowered.proxy.protocol.packets.Handshake;
+import org.junit.jupiter.api.Test;
+
+import static com.velocitypowered.proxy.protocol.ProtocolConstants.MINECRAFT_1_12;
+import static com.velocitypowered.proxy.protocol.ProtocolConstants.MINECRAFT_1_12_1;
+import static com.velocitypowered.proxy.protocol.ProtocolConstants.MINECRAFT_1_12_2;
+import static org.junit.jupiter.api.Assertions.*;
+
+class PacketRegistryTest {
+    private StateRegistry.PacketRegistry setupRegistry() {
+        StateRegistry.PacketRegistry registry = new StateRegistry.PacketRegistry(ProtocolConstants.Direction.CLIENTBOUND, StateRegistry.HANDSHAKE);
+        registry.register(Handshake.class, Handshake::new, new StateRegistry.PacketMapping(0x00, MINECRAFT_1_12));
+        return registry;
+    }
+
+    @Test
+    void packetRegistryWorks() {
+        StateRegistry.PacketRegistry registry = setupRegistry();
+        MinecraftPacket packet = registry.getVersion(MINECRAFT_1_12).createPacket(0);
+        assertNotNull(packet, "Packet was not found in registry");
+        assertEquals(Handshake.class, packet.getClass(), "Registry returned wrong class");
+
+        assertEquals(0, registry.getVersion(MINECRAFT_1_12).getPacketId(packet), "Registry did not return the correct packet ID");
+    }
+
+    @Test
+    void packetRegistryLinkingWorks() {
+        StateRegistry.PacketRegistry registry = setupRegistry();
+        MinecraftPacket packet = registry.getVersion(MINECRAFT_1_12_1).createPacket(0);
+        assertNotNull(packet, "Packet was not found in registry");
+        assertEquals(Handshake.class, packet.getClass(), "Registry returned wrong class");
+        assertEquals(0, registry.getVersion(MINECRAFT_1_12_1).getPacketId(packet), "Registry did not return the correct packet ID");
+    }
+
+    @Test
+    void failOnNoMappings() {
+        StateRegistry.PacketRegistry registry = new StateRegistry.PacketRegistry(ProtocolConstants.Direction.CLIENTBOUND, StateRegistry.HANDSHAKE);
+        assertThrows(IllegalArgumentException.class, () -> registry.register(Handshake.class, Handshake::new));
+        assertThrows(IllegalArgumentException.class, () -> registry.getVersion(0).getPacketId(new Handshake()));
+    }
+
+    @Test
+    void registrySuppliesCorrectPacketsByProtocol() {
+        StateRegistry.PacketRegistry registry = new StateRegistry.PacketRegistry(ProtocolConstants.Direction.CLIENTBOUND, StateRegistry.HANDSHAKE);
+        registry.register(Handshake.class, Handshake::new, new StateRegistry.PacketMapping(0x00, MINECRAFT_1_12),
+                new StateRegistry.PacketMapping(0x01, MINECRAFT_1_12_1));
+        assertEquals(Handshake.class, registry.getVersion(MINECRAFT_1_12).createPacket(0x00).getClass());
+        assertEquals(Handshake.class, registry.getVersion(MINECRAFT_1_12_1).createPacket(0x01).getClass());
+        assertEquals(Handshake.class, registry.getVersion(MINECRAFT_1_12_2).createPacket(0x01).getClass());
+    }
+}

proxy/src/test/java/com/velocitypowered/proxy/util/EncryptionUtilsTest.java

@@ -0,0 +1,26 @@
+package com.velocitypowered.proxy.util;
+
+import org.junit.jupiter.api.Test;
+
+import java.nio.charset.StandardCharsets;
+import java.security.MessageDigest;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class EncryptionUtilsTest {
+    @Test
+    void twosComplementHexdigest() throws Exception {
+        String notchHash = mojangLoginSha1("Notch");
+        assertEquals("4ed1f46bbe04bc756bcb17c0c7ce3e4632f06a48", notchHash);
+
+        String jebHash = mojangLoginSha1("jeb_");
+        assertEquals("-7c9d5b0044c130109a5d7b5fb5c317c02b4e28c1", jebHash);
+    }
+
+    private String mojangLoginSha1(String str) throws Exception {
+        MessageDigest digest = MessageDigest.getInstance("SHA-1");
+        digest.update(str.getBytes(StandardCharsets.UTF_8));
+        byte[] digested = digest.digest();
+        return EncryptionUtils.twosComplementHexdigest(digested);
+    }
+}

proxy/src/test/java/com/velocitypowered/proxy/util/UuidUtilsTest.java

@@ -0,0 +1,30 @@
+package com.velocitypowered.proxy.util;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.UUID;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class UuidUtilsTest {
+    private static final UUID EXPECTED_DASHED_UUID = UUID.fromString("6b501978-d3be-4f33-bcf6-6e7808f37a0d");
+    private static final String ACTUAL_UNDASHED_UUID = EXPECTED_DASHED_UUID.toString().replace("-", "");
+
+    private static final UUID TEST_OFFLINE_PLAYER_UUID = UUID.fromString("708f6260-183d-3912-bbde-5e279a5e739a");
+    private static final String TEST_OFFLINE_PLAYER = "tuxed";
+
+    @Test
+    void generateOfflinePlayerUuid() {
+        assertEquals(TEST_OFFLINE_PLAYER_UUID, UuidUtils.generateOfflinePlayerUuid(TEST_OFFLINE_PLAYER), "UUIDs do not match");
+    }
+
+    @Test
+    void fromUndashed() {
+        assertEquals(EXPECTED_DASHED_UUID, UuidUtils.fromUndashed(ACTUAL_UNDASHED_UUID), "UUIDs do not match");
+    }
+
+    @Test
+    void toUndashed() {
+        assertEquals(ACTUAL_UNDASHED_UUID, UuidUtils.toUndashed(EXPECTED_DASHED_UUID), "UUIDs do not match");
+    }
+}