Connection closed when using mock server

[ruiarodrigues]

Describe the bug

Hi!
I'm upgrade from 6.x to 7.3.1 and my tests fail with connection closed when the first request to the server is done. Everything works fine with 6.x. See the steps to reproduce the error.

Fabric8 Kubernetes Client version

7.3.1

Steps to reproduce

Run this

import io.fabric8.kubernetes.api.model.Pod;
import io.fabric8.kubernetes.api.model.PodBuilder;
import io.fabric8.kubernetes.client.KubernetesClient;
import io.fabric8.kubernetes.client.server.mock.EnableKubernetesMockClient;
import io.fabric8.kubernetes.client.server.mock.KubernetesMockServer;
import org.junit.jupiter.api.Test;

@EnableKubernetesMockClient
class SomeTest {

    KubernetesMockServer server;
    KubernetesClient client;

    @Test
    void myTest() {
        server.expect().get()
            .withPath("/api/v1/namespaces/my-namespace/pods/my-pod")
            .andReturn(200, new PodBuilder().build())
            .always();
        Pod pod = client.pods().inNamespace("my-namespace").withName("my-pod").get();
    }
}

Expected behavior

Tests should pass after the upograde

Runtime

Kubernetes (vanilla)

Kubernetes API Server version

1.33

Environment

macOS

Fabric8 Kubernetes Client Logs

INFO: MockWebServer[51150] starting to accept connections on localhost
May 23, 2025 3:43:37 PM io.fabric8.mockwebserver.MockWebServer info
INFO: MockWebServer[51150] done accepting connections

Connection was closed
io.fabric8.kubernetes.client.KubernetesClientException: Connection was closed
	at io.fabric8.kubernetes.client.dsl.internal.OperationSupport.waitForResult(OperationSupport.java:509)
	at io.fabric8.kubernetes.client.dsl.internal.OperationSupport.handleResponse(OperationSupport.java:524)
	at io.fabric8.kubernetes.client.dsl.internal.OperationSupport.handleGet(OperationSupport.java:467)
	at io.fabric8.kubernetes.client.dsl.internal.BaseOperation.handleGet(BaseOperation.java:792)
	at io.fabric8.kubernetes.client.dsl.internal.BaseOperation.requireFromServer(BaseOperation.java:193)
	at io.fabric8.kubernetes.client.dsl.internal.BaseOperation.get(BaseOperation.java:149)
	at io.fabric8.kubernetes.client.dsl.internal.BaseOperation.get(BaseOperation.java:98)
	at fi.relex.processor2.adapter.SomeTest.myTest(SomeTest.java:38)

Additional context

I have as dependencies. Maybe something is missing?

kubernetes-client-bom = { module = "io.fabric8:kubernetes-client-bom", version = "7.3.1" }

implementation("io.fabric8:kubernetes-client")

[manusa]

Seems like the exact same issue as #6847

Unfortunately, there's no way we can reproduce this, most of our tests are based in the mock server and work just fine.

Would you be able to provide a reproducer project?

[ruiarodrigues]

Hi! I will try to reproduce in a smaller project. The project is large and have ,a lot of submodules. OkHttp is being used in the project. Can this have some side effect since now vertx is used for the mock server?

[manusa]

OkHttp is being used in the project. Can this have some side effect since now vertx is used for the mock server?

It shouldn't have to be related to that.
However, this is probably the only notable difference with our main test suite, so it might be a possible cause.

[ruiarodrigues]

I'm not able to reproduce it in a simple project until now :(