diff --git a/README.md b/README.md
index b1d7fde..e9cd6ea 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,3 @@
 # Blokk
 ## To Do
-- Stop Using Spek
 - Support packet compression
diff --git a/blokk-api/build.gradle.kts b/blokk-api/build.gradle.kts
index ff428fa..afc7054 100644
--- a/blokk-api/build.gradle.kts
+++ b/blokk-api/build.gradle.kts
@@ -16,6 +16,8 @@ val moshiVersion = properties["version.moshi"].toString()
 val coroutinesVersion = properties["version.kotlinx-coroutines"].toString()
 val nettyVersion = properties["version.netty"].toString()
 val slf4jVersion = properties["version.slf4j"].toString()
+val junitVersion = properties["version.junit"].toString()
+val striktVersion = properties["version.strikt"].toString()
 
 dependencies {
     // Kotlin
@@ -33,9 +35,9 @@ dependencies {
     api("io.netty:netty-buffer:${nettyVersion}")
 
     // Testing
-    testImplementation("io.strikt:strikt-core:0.26.1")
-    testImplementation("org.junit.jupiter:junit-jupiter-api:5.6.2")
-    testRuntimeOnly("org.junit.jupiter:junit-jupiter-engine:5.6.2")
+    testImplementation("io.strikt:strikt-core:${striktVersion}")
+    testImplementation("org.junit.jupiter:junit-jupiter-api:${junitVersion}")
+    testRuntimeOnly("org.junit.jupiter:junit-jupiter-engine:${junitVersion}")
 }
 
 tasks {
diff --git a/blokk-api/src/main/kotlin/space/blokk/net/packets/Protocol.kt b/blokk-api/src/main/kotlin/space/blokk/net/packets/Protocol.kt
index 0c11342..fb7051e 100644
--- a/blokk-api/src/main/kotlin/space/blokk/net/packets/Protocol.kt
+++ b/blokk-api/src/main/kotlin/space/blokk/net/packets/Protocol.kt
@@ -3,7 +3,7 @@ package space.blokk.net.packets
 import kotlin.reflect.KClass
 
 abstract class Protocol constructor(val name: String, vararg codecs: PacketCodec<*>) {
-    val test = emptyList<Packet>()
+    val codecs = codecs.toSet()
     private val codecsByPacketType = codecs.map { it.dataType to it }.toMap()
     val incomingPacketCodecsByID = codecs.filterIsInstance<IncomingPacketCodec<*>>().map { it.id to it }.toMap()
 
diff --git a/blokk-packet-codecs/build.gradle.kts b/blokk-packet-codecs/build.gradle.kts
index 2073a52..301b44e 100644
--- a/blokk-packet-codecs/build.gradle.kts
+++ b/blokk-packet-codecs/build.gradle.kts
@@ -7,19 +7,35 @@ version = rootProject.version
 
 repositories {
     mavenCentral()
+    jcenter()
 }
 
 val nettyVersion = properties["version.netty"].toString()
+val junitVersion = properties["version.junit"].toString()
+val striktVersion = properties["version.strikt"].toString()
 
 dependencies {
     api(project(":blokk-packets"))
 
     // Netty
     api("io.netty:netty-buffer:${nettyVersion}")
+
+    // Testing
+    testImplementation("io.strikt:strikt-core:${striktVersion}")
+    testImplementation("org.junit.jupiter:junit-jupiter-api:${junitVersion}")
+    testRuntimeOnly("org.junit.jupiter:junit-jupiter-engine:${junitVersion}")
 }
 
 tasks {
     compileKotlin {
         kotlinOptions.jvmTarget = "1.8"
     }
+
+    compileTestKotlin {
+        kotlinOptions.jvmTarget = "1.8"
+    }
+
+    test {
+        useJUnitPlatform()
+    }
 }
diff --git a/blokk-packet-codecs/src/test/kotlin/space/blokk/net/packets/ProtocolValidationTest.kt b/blokk-packet-codecs/src/test/kotlin/space/blokk/net/packets/ProtocolValidationTest.kt
new file mode 100644
index 0000000..04e829c
--- /dev/null
+++ b/blokk-packet-codecs/src/test/kotlin/space/blokk/net/packets/ProtocolValidationTest.kt
@@ -0,0 +1,33 @@
+package space.blokk.net.packets
+
+import org.junit.jupiter.api.Test
+import space.blokk.net.packets.handshaking.HandshakingProtocol
+import space.blokk.net.packets.login.LoginProtocol
+import space.blokk.net.packets.play.PlayProtocol
+import space.blokk.net.packets.status.StatusProtocol
+
+class ProtocolValidationTest {
+    private fun ensureIDUniqueness(codecs: List<PacketCodec<*>>, type: String, protocol: Protocol) {
+        codecs.groupBy { it.id }.forEach { (id, c) ->
+            if (c.count() > 1) {
+                val packetsString = c.joinToString(", ", limit = 4) { it.dataType.simpleName.toString() }
+                throw AssertionError(
+                    "Multiple $type packets of the ${protocol.name} protocol use the same ID " +
+                            "(0x${id.toString(16)}): $packetsString"
+                )
+            }
+        }
+    }
+
+    @Test
+    fun `all packets have unique IDs in their protocol`() {
+        for (protocol in PROTOCOLS) {
+            ensureIDUniqueness(protocol.codecs.filterIsInstance<IncomingPacketCodec<*>>(), "incoming", protocol)
+            ensureIDUniqueness(protocol.codecs.filterIsInstance<OutgoingPacketCodec<*>>(), "outgoing", protocol)
+        }
+    }
+
+    companion object {
+        val PROTOCOLS = setOf(HandshakingProtocol, LoginProtocol, StatusProtocol, PlayProtocol)
+    }
+}
diff --git a/gradle.properties b/gradle.properties
index 9906446..a5d7b1b 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -4,3 +4,5 @@ version.netty=4.1.50.Final
 version.moshi=1.9.3
 version.kotlinx-coroutines=1.3.8
 version.slf4j=1.7.30
+version.junit=5.6.2
+version.strikt=0.26.1