How to make Microcks access my application during Quarkus integration tests

I developed a REST API Quarkus project based on an OpenAPI specification to validate contract testing with Microcks.

OpenAPI Specification

openapi: 3.0.0 x-stoplight: id: 1q8257l49074g info: title: SampleAPI version: '1.0' description: |- A sample API demonstrating OpenAPI 3.0 and Microcks integration. license: name: Apache 2.0 paths: /sender: get: tags: - Sender summary: Get All Senders description: Retrieves all sender entries. operationId: getAllSenders responses: '200': description: Successful response content: application/json: schema: type: array items: $ref: '#/components/schemas/SenderResult' examples: all: value: - id: 1 message: "Hello Receiver" status: "sent" - id: 2 message: "Another message" status: "pending" '500': description: Internal server error content: text/plain: schema: type: string example: "Internal Server Error" components: schemas: SenderResult: type: object required: - id - message - status properties: id: type: integer message: type: string status: type: string 

Resource Class

@Slf4j @ApplicationScoped public class SenderResource implements SenderApi { private final ReceiverClient receiverClient; // Simple in-memory cache simulating a database private final ConcurrentHashMap<Integer, SenderResult> senderCache = new ConcurrentHashMap<>(); @Inject public SenderResource(@RestClient ReceiverClient receiverClient) { this.receiverClient = receiverClient; log.info("Initializing SenderResource..."); // Default sender entry SenderResult defaultSender = new SenderResult() .id(1) .message("default") .status("success"); senderCache.put(defaultSender.getId(), defaultSender); // Another example sender SenderResult anotherSender = new SenderResult() .id(2) .message("another") .status("QUEUED"); senderCache.put(anotherSender.getId(), anotherSender); } /** * Retrieve all senders. */ @Override public Response getAllSenders() { return Response.ok(senderCache.values()).build(); } } 

Microcks Configuration

To enable Microcks integration, I added the following configuration in application.yaml:

quarkus: microcks: devservices: enabled: true 

And included the Quarkus Microcks dependency:

<dependency> <groupId>io.github.microcks.quarkus</groupId> <artifactId>quarkus-microcks</artifactId> <version>0.4.1</version> <scope>test</scope> </dependency> 

Contract Test

To verify that everything works, I created a contract test using Microcks:

@QuarkusTest @Slf4j public class SenderContractTest { static String microcksUrl; static Integer port; @BeforeAll static void init() { Config config = ConfigProvider.getConfig(); microcksUrl = config .getOptionalValue("quarkus.microcks.default.http", String.class) .orElse("http://localhost:8085"); port = config.getOptionalValue("quarkus.http.test-port", Integer.class) .orElse(8282); log.info("Microcks URL for contract tests: {}", microcksUrl); log.info("Test application port: {}", port); } @Test void testAllOperationsFromSenderOpenApi() throws Exception { String endpointUrl = "http://host.containers.internal:" + port; log.info("Endpoint URL for contract test: {}", endpointUrl); TestRequest request = new TestRequest.Builder() .serviceId("SenderAPI:1.0") .runnerType(TestRunnerType.OPEN_API_SCHEMA) .testEndpoint(endpointUrl) .build(); TestResult result = MicrocksContainer.testEndpoint(microcksUrl, request); assertNotNull(result, "A test result should be returned by Microcks"); logTestResultDetails(result); assertTrue(result.isSuccess(), "Contract test failed. See logs above for details."); assertEquals(5, result.getTestCaseResults().size(), "Number of test cases should match the number of operations (GET all, GET by ID, POST, DELETE)"); } } 

for the unit test was successfull

Integration Test Issue

However, when running the integration tests, I encountered the following error:

Server Version: 5.2.5 API Version: 1.41 Operating System: Fedora Total Memory: 7358 MB 2025-10-08 17:24:34,176 WARN [org.tes.uti.ResourceReaper] (build-9) ******************************************************************************** Ryuk has been disabled. This can cause unexpected behavior in your environment. ******************************************************************************** 2025-10-08 17:24:34,177 INFO [org.tes.DockerClientFactory] (build-9) Checking the system... 2025-10-08 17:24:34,178 INFO [org.tes.DockerClientFactory] (build-9) ✔︎ Docker server version should be at least 1.6.0 2025-10-08 17:24:34,181 INFO [org.tes.ima.PullPolicy] (build-9) Image pull policy will be performed by: DefaultPullPolicy() 2025-10-08 17:24:34,182 INFO [org.tes.uti.ImageNameSubstitutor] (build-9) Using DefaultImageNameSubstitutor 2025-10-08 17:24:34,370 INFO [tc.tes.2.0] (build-9) Creating container for image: testcontainers/sshd:1.2.0 2025-10-08 17:24:34,700 INFO [tc.tes.2.0] (build-9) Container testcontainers/sshd:1.2.0 started in PT0.33S 2025-10-08 17:24:34,740 INFO [tc.qua.io/microcks/microcks-uber:latest] (build-9) Creating container for image: quay.io/microcks/microcks-uber:latest 2025-10-08 17:24:37,331 INFO [tc.qua.io/microcks/microcks-uber:latest] (build-9) Container started in PT2.59S 2025-10-08 17:24:37,337 INFO [io.git.mic.qua.dep.DevServicesMicrocksProcessor] (build-9) Loading 'ReceiverAPI-1.0-openapi.yaml' as primary artifact 2025-10-08 17:24:37,568 INFO [io.git.mic.qua.dep.DevServicesMicrocksProcessor] (build-9) Loading 'SenderAPI-1.0-openapi.yaml' as primary artifact 2025-10-08 17:24:37,619 INFO [io.git.mic.qua.dep.DevServicesMicrocksProcessor] (build-9) Microcks container is ready at http://localhost:35299 2025-10-08 17:24:39,146 INFO [io.qua.tes.com.DefaultDockerContainerLauncher] (main) Executing: "podman run --name quarkus-integration-test-fjwjp -i --rm -p 56778:56778 -p 8444:8444 --net=14af332156f1842487acba7654ad746feb1099ed2aa07ebe44323b0e4a3d8008 --env QUARKUS_HTTP_PORT=56778 --env QUARKUS_MICROCKS_DEFAULT_HTTP=http://localhost:35299 samples/java-contract-testing-microcks:0.1-SNAPSHOT" 2025-10-08 17:24:42,293 INFO [io.qua.tes.com.DefaultDockerContainerLauncher] (main) Server started on port 56778 2025-10-08 17:24:42,346 INFO [com.ama.sam.sen.SenderContractTest] (main) Endpoint URL for contract test: http://host.containers.internal:56778 2025-10-08 17:24:42,356 INFO [io.qua.tes.com.DefaultDockerContainerLauncher] (main) Closing the container [ERROR] Tests run: 6, Failures: 1, Errors: 5, Skipped: 0, Time elapsed: 66.65 s <<< FAILURE! [ERROR] .samples.sender.SenderContractIT.testAllOperationsFromSenderOpenApi -- Time elapsed: 2.421 s <<< FAILURE! org.opentest4j.AssertionFailedError: Contract test failed for operation: GET /sender ==> expected: <true> but was: <false> at .samples.sender.SenderContractTest.testAllOperationsFromSenderOpenApi(SenderContractTest.java:150) [ERROR] .samples.sender.SenderContractIT.testAllOperationsFromSenderOpenApi -- Time elapsed: 0.861 s <<< ERROR! java.net.ConnectException: Connection refused at java.base/sun.nio.ch.Net.connect0(Native Method) at java.base/sun.nio.ch.Net.connect(Net.java:589) at java.base/sun.nio.ch.NioSocketImpl.connect(NioSocketImpl.java:583) at java.base/java.net.Socket.connect(Socket.java:751) ... at io.github.microcks.testcontainers.MicrocksContainer.testEndpoint(MicrocksContainer.java:519) 2025-10-08 17:24:44,908 INFO [com.git.doc.zer.sha.org.apa.hc.cli.htt.imp.cla.HttpRequestRetryExec] (Thread-739) Recoverable I/O exception (NoHttpResponseException) caught when processing request to unix://localhost:2375 Exception in multiple threads: com.github.dockerjava.api.exception.InternalServerErrorException: Status 500: {"cause":"no such container","message":"no container with ID ... found in database","response":500} at org.testcontainers.shaded.com.github.dockerjava.core.DefaultInvocationBuilder.execute(DefaultInvocationBuilder.java:247) at org.testcontainers.utility.JVMHookResourceReaper.prune(JVMHookResourceReaper.java:58) 

This indicates that the integration tests failed to connect to the running application within the container

How can I configure Quarkus Testcontainers and Microcks so that integration tests don’t fail with Connection refused when using Podman instead of Docker?