feat(extensions): add Elasticsearch Testcontainer support in usage module

- Added `testcontainers-elasticsearch` dependency to demonstrate user-managed Elasticsearch containers.
- Updated `DummyAppUsageTest` to include an Elasticsearch Testcontainer and validate coexistence with BigDataKit-managed services.
- Expanded README with examples of user-managed containers and their configuration.

Author: CoderYellow

example/app-extension/README.md

@@ -12,6 +12,12 @@ Modules:
 - `usage`: a test module showing how an application test uses `@BigDataTest`,
   `@BigDataExtensions`, and `@DummyAppTest` together.
 
+The `usage` module also starts a user-owned Elasticsearch Testcontainer with
+`org.testcontainers:testcontainers-elasticsearch`. This demonstrates that user
+Testcontainers can coexist with the containers managed by `bigdata-test`; keep
+those containers in the test or application extension code and let the BigData
+kit manage only the services declared through its own config.
+
 Run it with:
 
 ```bash

example/app-extension/usage/build.gradle.kts

@@ -10,6 +10,7 @@ dependencies {
     testImplementation(project(":example:app-extension:dummy-app-framework"))
     testImplementation(project(":example:app-extension:dummy-app-test-extension"))
     testImplementation(libs.junitJupiterApi)
+    testImplementation(libs.testcontainersElasticsearch)
     testRuntimeOnly(libs.junitJupiterEngine)
     testRuntimeOnly(libs.junitPlatformLauncher)
 }

example/app-extension/usage/src/test/kotlin/org/openprojectx/bigdata/test/example/app/usage/DummyAppUsageTest.kt

@@ -7,14 +7,24 @@ import org.openprojectx.bigdata.test.example.app.extension.DummyAppConfigCustomi
 import org.openprojectx.bigdata.test.example.app.extension.DummyAppTest
 import org.openprojectx.bigdata.test.example.app.framework.DummyApp
 import org.openprojectx.bigdata.test.example.app.framework.DummyAppConfig
+import org.openprojectx.bigdata.test.core.BigDataService
 import org.openprojectx.bigdata.test.extensions.core.BigDataExtensionResult
 import org.openprojectx.bigdata.test.extensions.junit5.BigDataExtensions
 import org.openprojectx.bigdata.test.core.BigDataTestKit
 import org.openprojectx.bigdata.test.junit5.BigDataTest
+import org.testcontainers.junit.jupiter.Container
+import org.testcontainers.junit.jupiter.Testcontainers
+import org.testcontainers.elasticsearch.ElasticsearchContainer
+import org.testcontainers.utility.DockerImageName
+import java.net.URI
+import java.net.http.HttpClient
+import java.net.http.HttpRequest
+import java.net.http.HttpResponse
 
-@BigDataTest
+@BigDataTest(localStackS3 = true)
 @BigDataExtensions
 @DummyAppTest
+@Testcontainers
 class DummyAppUsageTest : DummyAppConfigCustomizer {
     override fun customize(
         kit: BigDataTestKit,
@@ -34,4 +44,36 @@ class DummyAppUsageTest : DummyAppConfigCustomizer {
         assertEquals("usage-example", app.property("dummy.project.name"))
         assertEquals(config, app.config)
     }
+
+    @Test
+    fun `coexists with user managed elasticsearch testcontainer`(
+        app: DummyApp,
+        kit: BigDataTestKit,
+    ) {
+        val response = httpClient.send(
+            HttpRequest.newBuilder(URI.create("http://${elasticsearch.httpHostAddress}/_cluster/health"))
+                .GET()
+                .build(),
+            HttpResponse.BodyHandlers.ofString(),
+        )
+
+        assertTrue(app.started)
+        assertTrue(kit.endpoints().containsKey(BigDataService.LOCALSTACK_S3))
+        assertEquals(200, response.statusCode())
+        assertTrue(response.body().contains("\"cluster_name\""))
+    }
+
+    private companion object {
+        private val elasticsearchImage: DockerImageName =
+            DockerImageName.parse("ghcr.io/openprojectx/dockerhub/library/elasticsearch:8.19.18")
+                .asCompatibleSubstituteFor("docker.elastic.co/elasticsearch/elasticsearch")
+
+        @Container
+        @JvmField
+        val elasticsearch: ElasticsearchContainer = ElasticsearchContainer(elasticsearchImage)
+            .withEnv("xpack.security.enabled", "false")
+            .withEnv("xpack.security.http.ssl.enabled", "false")
+
+        private val httpClient: HttpClient = HttpClient.newHttpClient()
+    }
 }

gradle/libs.versions.toml

@@ -43,6 +43,7 @@ testcontainers = { module = "org.testcontainers:testcontainers" }
 testcontainersPostgresql = { module = "org.testcontainers:testcontainers-postgresql" }
 testcontainersMysql = { module = "org.testcontainers:testcontainers-mysql" }
 testcontainersKafka = { module = "org.testcontainers:testcontainers-kafka" }
+testcontainersElasticsearch = { module = "org.testcontainers:testcontainers-elasticsearch" }
 testcontainersJunitJupiter = { module = "org.testcontainers:testcontainers-junit-jupiter" }
 kafkaClients = { module = "org.apache.kafka:kafka-clients", version.ref = "kafka" }
 hiveDockerTestcontainers = { module = "org.openprojectx.hive.docker.core:hive-docker-testcontainers", version.ref = "hiveDockerTestcontainers" }