In unit tests, do ZK cache reloads in same thread, to avoid race conditions (#31)

pulsar-broker/src/main/java/com/yahoo/pulsar/broker/PulsarService.java

@@ -180,7 +180,7 @@ public class PulsarService implements AutoCloseable {
                 adminClient.close();
                 adminClient = null;
             }
-            
+
             nsservice = null;
 
             // executor is not initialized in mocks even when real close method is called
@@ -357,10 +357,10 @@ public class PulsarService implements AutoCloseable {
 
         LOG.info("starting configuration cache service");
 
-        this.localZkCache = new LocalZooKeeperCache(getZkClient(), this.orderedExecutor);
+        this.localZkCache = new LocalZooKeeperCache(getZkClient(), getOrderedExecutor());
         this.globalZkCache = new GlobalZooKeeperCache(getZooKeeperClientFactory(),
                 (int) config.getZooKeeperSessionTimeoutMillis(), config.getGlobalZookeeperServers(),
-                this.orderedExecutor, this.executor);
+                getOrderedExecutor(), this.executor);
         try {
             this.globalZkCache.start();
         } catch (IOException e) {

pulsar-broker/src/test/java/com/yahoo/pulsar/broker/auth/MockedPulsarServiceBaseTest.java

@@ -68,6 +68,8 @@ public abstract class MockedPulsarServiceBaseTest {
     protected MockZooKeeper mockZookKeeper;
     protected NonClosableMockBookKeeper mockBookKeeper;
 
+    private SameThreadOrderedSafeExecutor sameThreadOrderedSafeExecutor;
+
     public MockedPulsarServiceBaseTest() {
         this.conf = new ServiceConfiguration();
         this.conf.setBrokerServicePort(BROKER_PORT);
@@ -96,6 +98,8 @@ public abstract class MockedPulsarServiceBaseTest {
         mockZookKeeper = createMockZooKeeper();
         mockBookKeeper = new NonClosableMockBookKeeper(new ClientConfiguration(), mockZookKeeper);
 
+        sameThreadOrderedSafeExecutor = new SameThreadOrderedSafeExecutor();
+
         startBroker();
 
         brokerUrl = new URL("http://localhost:" + BROKER_WEBSERVICE_PORT);
@@ -110,6 +114,7 @@ public abstract class MockedPulsarServiceBaseTest {
         pulsar.close();
         mockBookKeeper.reallyShutdow();
         mockZookKeeper.shutdown();
+        sameThreadOrderedSafeExecutor.shutdown();
     }
 
     protected abstract void setup() throws Exception;
@@ -146,6 +151,8 @@ public abstract class MockedPulsarServiceBaseTest {
 
         Supplier<NamespaceService> namespaceServiceSupplier = () -> spy(new NamespaceService(pulsar));
         doReturn(namespaceServiceSupplier).when(pulsar).getNamespaceServiceProvider();
+
+        doReturn(sameThreadOrderedSafeExecutor).when(pulsar).getOrderedExecutor();
     }
 
     private MockZooKeeper createMockZooKeeper() throws Exception {

pulsar-broker/src/test/java/com/yahoo/pulsar/broker/auth/SameThreadOrderedSafeExecutor.java

+/**
+ * Copyright 2016 Yahoo Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.yahoo.pulsar.broker.auth;
+
+import org.apache.bookkeeper.util.OrderedSafeExecutor;
+import org.apache.bookkeeper.util.SafeRunnable;
+
+public class SameThreadOrderedSafeExecutor extends OrderedSafeExecutor {
+
+    public SameThreadOrderedSafeExecutor() {
+        super(1, "ordered-executor");
+    }
+
+    @Override
+    public void submit(SafeRunnable r) {
+        r.run();
+    }
+
+    @Override
+    public void submitOrdered(int orderingKey, SafeRunnable r) {
+        r.run();
+    }
+
+    @Override
+    public void submitOrdered(long orderingKey, SafeRunnable r) {
+        r.run();
+    }
+
+    @Override
+    public void submitOrdered(Object orderingKey, SafeRunnable r) {
+        r.run();
+    }
+}