fix: update for jdk21

build.gradle.kts

@@ -9,6 +9,7 @@ version = "1.3.0"
 
 val invuiVersion: String = "1.46"
 val jacksonVersion: String = "2.20.0"
+val mockBukkitVersion: String = "4.72.8"
 
 java {
     sourceCompatibility = JavaVersion.VERSION_21
@@ -20,8 +21,8 @@ java {
 }
 
 repositories {
-    mavenCentral()
     mavenLocal()
+    mavenCentral()
 
     maven("https://repo.xenondevs.xyz/releases")
     maven("https://repo.papermc.io/repository/maven-public/")
@@ -47,9 +48,20 @@ dependencies {
     implementation("org.mariadb.jdbc:mariadb-java-client:3.5.2")
     implementation("redis.clients:jedis:5.2.0")
     implementation("com.google.code.gson:gson:2.13.1")
+
+    testImplementation("org.mockbukkit.mockbukkit:mockbukkit-v1.21:$mockBukkitVersion")
+    testImplementation(platform("org.junit:junit-bom:5.13.4"))
+    testImplementation("org.junit.jupiter:junit-jupiter")
+    testRuntimeOnly("org.junit.platform:junit-platform-launcher")
 }
 
 tasks {
+    test {
+        useJUnitPlatform()
+        testLogging {
+            events("passed", "skipped", "failed")
+        }
+    }
 
     processResources {
         from("src/main/resources")