add kafka test container

src/main/kotlin/ltd/hlaeja/test/container/extension/KafkaTestExtension.kt

@@ -0,0 +1,21 @@
+package ltd.hlaeja.test.container.extension
+
+import ltd.hlaeja.test.container.kafka.TestContainerKafka
+import org.junit.jupiter.api.extension.BeforeAllCallback
+import org.junit.jupiter.api.extension.ExtensionContext
+import org.springframework.boot.test.util.TestPropertyValues
+import org.springframework.context.ApplicationContextInitializer
+import org.springframework.context.ConfigurableApplicationContext
+
+class KafkaTestExtension : BeforeAllCallback, ApplicationContextInitializer<ConfigurableApplicationContext> {
+
+    override fun initialize(applicationContext: ConfigurableApplicationContext) {
+        TestPropertyValues.of(TestContainerKafka.props()).applyTo(applicationContext.environment)
+    }
+
+    override fun beforeAll(context: ExtensionContext) {
+        if (!TestContainerKafka.kafka.isRunning) {
+            TestContainerKafka.kafka.start()
+        }
+    }
+}