Mock out the settting up k8 client part (#2726)

pulsar-functions/runtime/src/main/java/org/apache/pulsar/functions/runtime/KubernetesRuntimeFactory.java

@@ -141,7 +141,8 @@ public class KubernetesRuntimeFactory implements RuntimeFactory {
         KubernetesRuntime.doChecks(functionDetails);
     }
 
-    private void setupClient() throws Exception {
+    @VisibleForTesting
+    void setupClient() throws Exception {
         if (appsClient == null) {
             if (k8Uri == null) {
                 log.info("k8Uri is null thus going by defaults");

pulsar-functions/runtime/src/test/java/org/apache/pulsar/functions/runtime/KubernetesRuntimeTest.java

@@ -32,6 +32,8 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import static org.powermock.api.mockito.PowerMockito.doNothing;
+import static org.powermock.api.mockito.PowerMockito.spy;
 import static org.testng.Assert.assertEquals;
 
 /**
@@ -67,8 +69,9 @@ public class KubernetesRuntimeTest {
         this.pulsarAdminUrl = "http://localhost:8080";
         this.stateStorageServiceUrl = "bk://localhost:4181";
         this.logDirectory = "logs/functions";
-        this.factory = new KubernetesRuntimeFactory(null, null, null, null,
-            false, null, pulsarServiceUrl, pulsarAdminUrl, stateStorageServiceUrl, null);
+        this.factory = spy(new KubernetesRuntimeFactory(null, null, null, null,
+            false, null, pulsarServiceUrl, pulsarAdminUrl, stateStorageServiceUrl, null));
+        doNothing().when(this.factory).setupClient();
     }
 
     @AfterMethod