VOL-2710: Add unit test cases for kafka-onos

Change-Id: Ieff0a32b3552eb8843fa933e57fa4148cb54853b
diff --git a/src/test/java/org/opencord/kafka/impl/KafkaIntegrationTest.java b/src/test/java/org/opencord/kafka/impl/KafkaIntegrationTest.java
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@@ -0,0 +1,207 @@
+/*
+ * Copyright 2018-present Open Networking Foundation
+ *
+ * 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 org.opencord.kafka.impl;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.onosproject.cluster.ClusterServiceAdapter;
+import org.onosproject.core.ApplicationId;
+import org.onosproject.core.CoreServiceAdapter;
+import org.onosproject.net.config.Config;
+import org.onosproject.net.config.ConfigApplyDelegate;
+import org.onosproject.net.config.NetworkConfigEvent;
+import org.onosproject.net.config.NetworkConfigListener;
+import org.onosproject.net.config.NetworkConfigRegistryAdapter;
+
+import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * set of unit test to verify KafkaIntegration.
+ */
+class KafkaIntegrationTest {
+    private static final String ASSERT_MESSAGE = "Config not updated";
+    private static final String BOOTSTRAP_SERVERS = "localhost:9092";
+    protected NetworkConfigListener configListener;
+    protected ConfigApplyDelegate delegate;
+    protected ObjectMapper mapper;
+    protected ApplicationId subject;
+    protected NetworkConfigEvent event;
+    private KafkaConfig config = new KafkaConfig();
+    private KafkaIntegration kafkaIntegration;
+
+    @BeforeEach
+    public void setUp() throws Exception {
+        kafkaIntegration = new KafkaIntegration();
+        kafkaIntegration.coreService = new MockCoreService();
+        kafkaIntegration.clusterService = new ClusterServiceAdapter();
+        setupConfig("/localKafkaConfig.json");
+        kafkaIntegration.activate();
+    }
+
+    @AfterEach
+    public void tearDown() {
+        kafkaIntegration.deactivate();
+        kafkaIntegration = null;
+    }
+
+    /**
+     * Local configuration verification using Resources file.
+     */
+    @Test
+    void testConfigAdded() {
+        event = new NetworkConfigEvent(NetworkConfigEvent.Type.CONFIG_ADDED, subject,
+                config, null, KafkaConfig.class);
+        configListener.event(event);
+        KafkaConfig expectedConfig = kafkaIntegration.configRegistry
+                .getConfig(kafkaIntegration.coreService.getAppId(KafkaIntegration.APP_NAME),
+                        KafkaConfig.class);
+        assertEquals(ASSERT_MESSAGE, BOOTSTRAP_SERVERS, expectedConfig.getBootstrapServers());
+    }
+
+    public void setupConfig(String localConfig) throws Exception {
+        delegate = new MockConfigDelegate();
+        mapper = new ObjectMapper();
+        subject = kafkaIntegration.coreService.registerApplication(KafkaIntegration.APP_NAME);
+        config.init(subject, "kafka-local-mode-test", node(localConfig), mapper, delegate);
+        kafkaIntegration.configRegistry = new MockNetworkConfigRegistry(subject, config);
+    }
+
+    protected JsonNode node(String jsonFile) throws Exception {
+        final InputStream jsonStream = KafkaConfig.class.getResourceAsStream(jsonFile);
+        return mapper.readTree(jsonStream);
+    }
+
+    /**
+     * Mocks an ONOS configuration delegate to allow JSON based configuration to
+     * be tested.
+     */
+    private static final class MockConfigDelegate implements ConfigApplyDelegate {
+        @Override
+        public void onApply(@SuppressWarnings("rawtypes") Config config) {
+            config.apply();
+        }
+    }
+
+    /**
+     * Mocks Core service adapter.
+     */
+    private static class MockCoreService extends CoreServiceAdapter {
+
+        private List<ApplicationId> idList = new ArrayList<>();
+        private Map<String, ApplicationId> idMap = new HashMap<>();
+
+        /*
+         * (non-Javadoc)
+         *
+         * @see
+         * org.onosproject.core.CoreServiceAdapter#getAppId(java.lang.Short)
+         */
+        @Override
+        public ApplicationId getAppId(Short id) {
+            if (id >= idList.size()) {
+                return null;
+            }
+            return idList.get(id);
+        }
+
+        /*
+         * (non-Javadoc)
+         *
+         * @see
+         * org.onosproject.core.CoreServiceAdapter#getAppId(java.lang.String)
+         */
+        @Override
+        public ApplicationId getAppId(String name) {
+            return idMap.get(name);
+        }
+
+        /*
+         * (non-Javadoc)
+         *
+         * @see
+         * org.onosproject.core.CoreServiceAdapter#registerApplication(java.lang
+         * .String)
+         */
+        @Override
+        public ApplicationId registerApplication(String name) {
+            ApplicationId appId = idMap.get(name);
+            if (appId == null) {
+                appId = new MockApplicationId((short) idList.size(), name);
+                idList.add(appId);
+                idMap.put(name, appId);
+            }
+            return appId;
+        }
+    }
+
+    /*
+   Mocks application id.
+    */
+    private static class MockApplicationId implements ApplicationId {
+
+        private final short id;
+        private final String name;
+
+        public MockApplicationId(short id, String name) {
+            this.id = id;
+            this.name = name;
+        }
+
+        @Override
+        public short id() {
+            return id;
+        }
+
+        @Override
+        public String name() {
+            return name;
+        }
+    }
+
+
+    /**
+     * Mocks the ONOS network configuration registry so that the application
+     * under test can access a JSON defined configuration.
+     */
+    private class MockNetworkConfigRegistry<S> extends NetworkConfigRegistryAdapter {
+        private final KafkaConfig config;
+
+        public MockNetworkConfigRegistry(final S subject, final KafkaConfig config) {
+            this.config = config;
+        }
+
+        @SuppressWarnings("unchecked")
+        @Override
+        public <S, C extends Config<S>> C getConfig(final S subject, final Class<C> configClass) {
+            return (C) config;
+        }
+
+        @Override
+        public void addListener(NetworkConfigListener listener) {
+            configListener = listener;
+        }
+    }
+}
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