diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
new file mode 100644
index 0000000..b93076a
--- /dev/null
+++ b/.github/workflows/test.yml
@@ -0,0 +1,21 @@
+name: Test
+on:
+  push:
+    branches:
+      - '*'
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    name: "Test"
+    steps:
+      - uses: actions/checkout@v2
+      - name: Setup git
+        run: 'git config --global user.email "actions@github.com" && git config --global user.name "GitHub Actions"'
+      - name: Setup Java JDK
+        uses: actions/setup-java@v2.3.1
+        with:
+          java-version: 17
+          distribution: temurin
+          cache: 'gradle'
+      - name: Run tests
+        run: ./gradlew clean test
diff --git a/api/build.gradle.kts b/api/build.gradle.kts
index 529692c..67535c1 100644
--- a/api/build.gradle.kts
+++ b/api/build.gradle.kts
@@ -2,4 +2,5 @@ dependencies {
     api("org.yaml:snakeyaml:1.30")
     compileOnlyApi("org.jetbrains:annotations:23.0.0")
     compileOnlyApi("net.luckperms:api:5.4")
+    testRuntimeOnly("net.luckperms:api:5.4")
 }
diff --git a/api/src/main/java/net/azisaba/azipluginmessaging/api/protocol/Protocol.java b/api/src/main/java/net/azisaba/azipluginmessaging/api/protocol/Protocol.java
index 23c7fd2..7852bf2 100644
--- a/api/src/main/java/net/azisaba/azipluginmessaging/api/protocol/Protocol.java
+++ b/api/src/main/java/net/azisaba/azipluginmessaging/api/protocol/Protocol.java
@@ -55,8 +55,8 @@ public final class Protocol<T extends MessageHandler<M>, M extends Message> {
     public static final Protocol<ProxyboundToggleGamingSaraPacket, PlayerMessage> P_TOGGLE_GAMING_SARA = new Protocol<>(PacketFlow.TO_PROXY, 0x04, new ProxyboundToggleGamingSaraPacket());
     public static final Protocol<ProxyboundToggleSaraHidePacket, PlayerMessage> P_TOGGLE_SARA_HIDE = new Protocol<>(PacketFlow.TO_PROXY, 0x05, new ProxyboundToggleSaraHidePacket()); // non-contextual
     public static final Protocol<ProxyboundToggleSaraShowPacket, PlayerWithServerMessage> P_TOGGLE_SARA_SHOW = new Protocol<>(PacketFlow.TO_PROXY, 0x06, new ProxyboundToggleSaraShowPacket()); // contextual
-    public static final Protocol<ProxyboundSetPrefixPacket, ProxyboundSetPrefixMessage> P_SET_PREFIX = new Protocol<>(PacketFlow.TO_PROXY, 0x06, new ProxyboundSetPrefixPacket());
-    public static final Protocol<ProxyboundClearPrefixPacket, ProxyboundClearPrefixMessage> P_CLEAR_PREFIX = new Protocol<>(PacketFlow.TO_PROXY, 0x06, new ProxyboundClearPrefixPacket());
+    public static final Protocol<ProxyboundSetPrefixPacket, ProxyboundSetPrefixMessage> P_SET_PREFIX = new Protocol<>(PacketFlow.TO_PROXY, 0x07, new ProxyboundSetPrefixPacket());
+    public static final Protocol<ProxyboundClearPrefixPacket, ProxyboundClearPrefixMessage> P_CLEAR_PREFIX = new Protocol<>(PacketFlow.TO_PROXY, 0x08, new ProxyboundClearPrefixPacket());
 
     public static final Protocol<ServerboundEncryptionPacket, EncryptionMessage> S_ENCRYPTION = new Protocol<>(PacketFlow.TO_SERVER, 0x00, new ServerboundEncryptionPacket());
     public static final Protocol<ServerboundActionResponsePacket, ServerboundActionResponseMessage> S_ACTION_RESPONSE = new Protocol<>(PacketFlow.TO_SERVER, 0x01, new ServerboundActionResponsePacket());
diff --git a/api/src/test/java/net/azisaba/azipluginmessaging/test/ProtocolTest.java b/api/src/test/java/net/azisaba/azipluginmessaging/test/ProtocolTest.java
new file mode 100644
index 0000000..7535d82
--- /dev/null
+++ b/api/src/test/java/net/azisaba/azipluginmessaging/test/ProtocolTest.java
@@ -0,0 +1,12 @@
+package net.azisaba.azipluginmessaging.test;
+
+import net.azisaba.azipluginmessaging.api.protocol.PacketFlow;
+import net.azisaba.azipluginmessaging.api.protocol.Protocol;
+import org.junit.jupiter.api.Test;
+
+public class ProtocolTest {
+    @Test
+    public void load() {
+        Protocol.getById(PacketFlow.TO_SERVER, (byte) 0);
+    }
+}
diff --git a/build.gradle.kts b/build.gradle.kts
index 1cde183..7004d6d 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -35,6 +35,17 @@ subprojects {
     repositories {
         mavenCentral()
     }
+
+    dependencies {
+        testImplementation("org.junit.jupiter:junit-jupiter-api:5.8.2")
+        testRuntimeOnly("org.junit.jupiter:junit-jupiter-engine:5.8.2")
+    }
+
+    tasks {
+        test {
+            useJUnitPlatform()
+        }
+    }
 }
 
 allprojects {
diff --git a/gradlew b/gradlew
old mode 100644
new mode 100755