GitHub - java-operator-sdk/jenvtest: Kubernetes Integration Test Support for Java. Moved to fabric8 client: https://github.com/fabric8io/kubernetes-client/blob/main/doc/kube-api-test.md

⚠️ MOVED Jenvtest was renamed to kube-api-test and moved to be part of Fabric8 Kubernetes Client

jenvtest makes it easy to implement integration tests with Kubernetes API Server in Java. Inspired by envtest in Kubebuilder (Golang).

It runs the API Server binaries directly (without nodes and other components, but with etcd). Linux, Windows, Mac is supported.

See also this blog post regarding the motivation and more.

Docs

See more documentation in docs directory.

Usage

Include dependency:

<dependency>
    <groupId>io.javaoperatorsdk</groupId>
    <artifactId>jenvtest</artifactId>
    <version>[version]</version>
    <scope>test</scope>
</dependency>

In Unit Tests

See sample unit test here

@EnableKubeAPIServer
class JUnitExtensionSimpleCaseTest {

    // Use @KubeConfig annotation to inject kube config yaml to init any client
    @KubeConfig
    static String kubeConfigYaml;

    @Test
    void simpleTestWithTargetVersion() {
        var client = new KubernetesClientBuilder()
                .withConfig(Config.fromKubeconfig(kubeConfigYaml))
                .build();

        client.resource(TestUtils.testConfigMap()).create();
        var cm = client.resource(TestUtils.testConfigMap()).get();

        Assertions.assertThat(cm).isNotNull();
    }
}

Public API

The underlying API can be used directly. See KubeApiServer

See it's usage in a test.

class KubeApiServerTest {
    
    @Test
    void apiServerTest() {
        var kubeApi = new KubeAPIServer();
        kubeApi.start();

        var client =  new KubernetesClientBuilder()
                .withConfig(Config.fromKubeconfig(kubeApi.getKubeConfigYaml()))
                .build();
        
        client.resource(TestUtils.testConfigMap()).create();
        
        var cm = client.resource(TestUtils.testConfigMap()).get();
        Assertions.assertThat(cm).isNotNull();
        
        kubeApi.stop();
    }
}

Fabric8 Kubernetes Client Support

There is dedicated support for Fabric8 Kubernetes Client.

Using dependency:

<dependency>
    <groupId>io.javaoperatorsdk</groupId>
    <artifactId>jenvtest-fabric8-client-support</artifactId>
    <version>[version]</version>
    <scope>test</scope>
</dependency>

The client can be directly injected to the test. See sample test here.

@EnableKubeAPIServer
class JUnitFabric8ClientInjectionTest {

    static KubernetesClient client;
   
    // emitted code     
}

Support for Parallel Execution in Junit5

Parallel test execution is explicitly supported for JUnit5, in fact the project tests are running parallel. Running a new instance for each test case. This speeds up the tests (in our case >75%) in a way that test cases are also fully isolated from each other. See the surefire plugin config.

Testing Mutation and Validation Webhooks

An additional benefits os running K8S API Server this way, is that it makes easy to test Conversion Hooks and/or Dynamic Admission Controllers

In general, it is a best practice to use additional standard frameworks to implement Kubernetes webhooks, like kubernetes-webooks-framework with Quarkus or Spring. However, we demonstrate how it works in this test