ci: run integration tests in parallel forks

AGENTS.md

@@ -72,9 +72,12 @@ java-operator-sdk/
 # Run unit tests only
 ./mvnw test
 
-# Run integration tests
+# Run integration tests (test classes run in parallel in 5 forked JVMs)
 ./mvnw verify -Pintegration-tests
 
+# Run integration tests with a different parallelism (1 = sequential)
+./mvnw verify -Pintegration-tests -Dit.fork.count=1
+
 # Run specific test class
 ./mvnw test -Dtest=ClassName
 
@@ -125,6 +128,11 @@ java-operator-sdk/
 - Test against real Kubernetes API (typically via test cluster like minikube or kind)
 - Suffix with `IT` (e.g., `MyReconcilerIT`)
 - Located in `src/test/java`
+- Integration test classes run in parallel against the same cluster, so they must not depend on
+  cluster-wide state: use the namespace provided by the extension, unique names for cluster-scoped
+  resources, do not modify shared files such as the kubeconfig, and do not rely on a CRD being
+  absent or deleted after the test (CRDs are not deleted in the `integration-tests` profile, since
+  test classes share them). Distinct CRDs must not declare the same short name.
 
 ### Test Resources
 

operator-framework/src/test/java/io/javaoperatorsdk/operator/baseapi/cleanerforreconciler/CleanerForReconcilerCustomResource.java

@@ -25,6 +25,6 @@
 @Group("sample.javaoperatorsdk")
 @Version("v1")
 @Kind("CleanerForReconcilerCustomResource")
-@ShortNames("cfr")
+@ShortNames("cfrc")
 public class CleanerForReconcilerCustomResource extends CustomResource<Void, String>
     implements Namespaced {}

operator-framework/src/test/java/io/javaoperatorsdk/operator/baseapi/ownerreferencemultiversion/OwnerRefMultiVersionIT.java

@@ -16,7 +16,10 @@
 package io.javaoperatorsdk.operator.baseapi.ownerreferencemultiversion;
 
 import java.time.Duration;
+import java.util.Objects;
+import java.util.concurrent.TimeUnit;
 
+import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.RegisterExtension;
 import org.slf4j.Logger;
@@ -70,6 +73,13 @@ class OwnerRefMultiVersionIT {
               })
           .build();
 
+  @AfterEach
+  void deleteModifiedCrd() {
+    var crdClient = operator.getKubernetesClient().apiextensions().v1().customResourceDefinitions();
+    crdClient.withName(CRD_NAME).delete();
+    crdClient.withName(CRD_NAME).waitUntilCondition(Objects::isNull, 60, TimeUnit.SECONDS);
+  }
+
   @Test
   void mapperWorksAcrossVersionChange() {
     var reconciler = operator.getReconcilerOfType(OwnerRefMultiVersionReconciler.class);

operator-framework/src/test/java/io/javaoperatorsdk/operator/baseapi/shardselector/ShardSelectorIT.java

@@ -22,7 +22,9 @@
 import org.junit.jupiter.api.Test;
 
 import io.fabric8.kubeapitest.junit.EnableKubeAPIServer;
+import io.fabric8.kubeapitest.junit.KubeConfig;
 import io.fabric8.kubernetes.api.model.ObjectMetaBuilder;
+import io.fabric8.kubernetes.client.Config;
 import io.fabric8.kubernetes.client.KubernetesClient;
 import io.fabric8.kubernetes.client.KubernetesClientBuilder;
 import io.javaoperatorsdk.annotation.Sample;
@@ -44,10 +46,12 @@
         """)
 @EnableKubeAPIServer(
     kubeAPIVersion = "1.36.*",
-    apiServerFlags = {"--feature-gates=ShardedListAndWatch=true"},
-    updateKubeConfigFile = true)
+    apiServerFlags = {"--feature-gates=ShardedListAndWatch=true"})
 class ShardSelectorIT {
 
+  // injected by Kube API Test, the shared kubeconfig file is intentionally not modified
+  @KubeConfig static String kubeConfigYaml;
+
   // The two selectors split the 64-bit UID hash space in half: [0x0, 0x8000000000000000) and
   // [0x8000000000000000, 0x10000000000000000). Together they cover the whole space with no overlap,
   // so every resource is owned by exactly one shard.
@@ -59,7 +63,7 @@ class ShardSelectorIT {
   private static final String TEST_RESOURCE_NAME = "shard-test1";
   private static final Duration EVENT_SETTLE_WINDOW = Duration.ofMillis(500);
 
-  private final KubernetesClient adminClient = new KubernetesClientBuilder().build();
+  private final KubernetesClient adminClient = newClient();
 
   private Operator operator1;
   private Operator operator2;
@@ -104,7 +108,7 @@ void onlyOneShardReconcilesTheResource() {
 
   private ShardSelectorTestReconciler startOperatorForShard(String shardSelector) {
     var reconciler = new ShardSelectorTestReconciler();
-    var operator = new Operator(o -> o.withKubernetesClient(new KubernetesClientBuilder().build()));
+    var operator = new Operator(o -> o.withKubernetesClient(newClient()));
     operator.register(reconciler, o -> o.withShardSelector(shardSelector));
     operator.start();
     if (operator1 == null) {
@@ -115,6 +119,10 @@ private ShardSelectorTestReconciler startOperatorForShard(String shardSelector)
     return reconciler;
   }
 
+  private static KubernetesClient newClient() {
+    return new KubernetesClientBuilder().withConfig(Config.fromKubeconfig(kubeConfigYaml)).build();
+  }
+
   private ShardSelectorTestCustomResource testCustomResource() {
     var resource = new ShardSelectorTestCustomResource();
     resource.setMetadata(new ObjectMetaBuilder().withName(TEST_RESOURCE_NAME).build());

operator-framework/src/test/java/io/javaoperatorsdk/operator/dependent/cleanermanageddependent/CleanerForManagedDependentCustomResource.java

@@ -25,6 +25,6 @@
 @Group("sample.javaoperatorsdk")
 @Version("v1")
 @Kind("CleanerForReconcilerCustomResource")
-@ShortNames("cfr")
+@ShortNames("cfmd")
 public class CleanerForManagedDependentCustomResource extends CustomResource<Void, String>
     implements Namespaced {}

operator-framework/src/test/java/io/javaoperatorsdk/operator/dependent/dependentannotationsecondarymapper/DependentAnnotationSecondaryMapperResource.java

@@ -25,6 +25,6 @@
 @Group("sample.javaoperatorsdk")
 @Version("v1")
 @Kind("MaxIntervalTestCustomResource")
-@ShortNames("mit")
+@ShortNames("dasm")
 public class DependentAnnotationSecondaryMapperResource extends CustomResource<Void, Void>
     implements Namespaced {}

operator-framework/src/test/java/io/javaoperatorsdk/operator/workflow/crdpresentactivation/CRDPresentActivationConditionIT.java

@@ -17,6 +17,8 @@
 
 import java.time.Duration;
 import java.util.Map;
+import java.util.Objects;
+import java.util.concurrent.TimeUnit;
 
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.RegisterExtension;
@@ -53,11 +55,13 @@ public class CRDPresentActivationConditionIT {
   @Test
   void resourceCreatedOnlyIfCRDPresent() {
     // deleted so test can be repeated
-    extension
-        .getKubernetesClient()
-        .resources(CustomResourceDefinition.class)
-        .withName(CRD_NAME)
-        .delete();
+    var crdResource =
+        extension
+            .getKubernetesClient()
+            .resources(CustomResourceDefinition.class)
+            .withName(CRD_NAME);
+    crdResource.delete();
+    crdResource.waitUntilCondition(Objects::isNull, 60, TimeUnit.SECONDS);
 
     var resource = extension.create(testResource());
 
@@ -77,6 +81,16 @@ void resourceCreatedOnlyIfCRDPresent() {
               assertThat(dr).isNull();
             });
 
+    // the workflow, thus the CRD presence check, runs before the reconcile method
+    await()
+        .untilAsserted(
+            () ->
+                assertThat(
+                        extension
+                            .getReconcilerOfType(CRDPresentActivationReconciler.class)
+                            .getNumberOfExecutions())
+                    .isPositive());
+
     LocallyRunOperatorExtension.applyCrd(
         CRDPresentActivationDependentCustomResource.class, extension.getKubernetesClient());
 

operator-framework/src/test/java/io/javaoperatorsdk/operator/workflow/crdpresentactivation/CRDPresentActivationReconciler.java

@@ -15,6 +15,8 @@
  */
 package io.javaoperatorsdk.operator.workflow.crdpresentactivation;
 
+import java.util.concurrent.atomic.AtomicInteger;
+
 import io.javaoperatorsdk.operator.api.reconciler.*;
 import io.javaoperatorsdk.operator.api.reconciler.dependent.Dependent;
 import io.javaoperatorsdk.operator.processing.dependent.workflow.CRDPresentActivationCondition;
@@ -31,14 +33,20 @@ public class CRDPresentActivationReconciler
     implements Reconciler<CRDPresentActivationCustomResource>,
         Cleaner<CRDPresentActivationCustomResource> {
 
+  private final AtomicInteger numberOfExecutions = new AtomicInteger(0);
+
   @Override
   public UpdateControl<CRDPresentActivationCustomResource> reconcile(
       CRDPresentActivationCustomResource resource,
       Context<CRDPresentActivationCustomResource> context) {
-
+    numberOfExecutions.incrementAndGet();
     return UpdateControl.noUpdate();
   }
 
+  public int getNumberOfExecutions() {
+    return numberOfExecutions.get();
+  }
+
   @Override
   public DeleteControl cleanup(
       CRDPresentActivationCustomResource resource,

pom.xml

@@ -461,8 +461,17 @@
   <profiles>
     <profile>
       <id>integration-tests</id>
+      <properties>
+        <it.fork.count>5</it.fork.count>
+      </properties>
       <build>
         <plugins>
+          <!--
+            Integration tests run in parallel: each test class gets its own namespace, and test
+            classes are spread over it.fork.count JVMs (e.g. -Dit.fork.count=1 to run sequentially).
+            CRDs are not deleted after a test class (testsuite.deleteCRDs=false) since multiple test
+            classes share the same CRDs and one deleting it would break the others.
+          -->
           <plugin>
             <groupId>org.apache.maven.plugins</groupId>
             <artifactId>maven-surefire-plugin</artifactId>
@@ -474,6 +483,11 @@
                 <exclude>**/*Test.java</exclude>
                 <exclude>**/*E2E.java</exclude>
               </excludes>
+              <forkCount>${it.fork.count}</forkCount>
+              <reuseForks>true</reuseForks>
+              <systemPropertyVariables>
+                <testsuite.deleteCRDs>false</testsuite.deleteCRDs>
+              </systemPropertyVariables>
             </configuration>
           </plugin>
         </plugins>