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

Change-Id: Ieff0a32b3552eb8843fa933e57fa4148cb54853b
diff --git a/src/test/java/org/opencord/kafka/integrations/BngStatsKafkaIntegrationTest.java b/src/test/java/org/opencord/kafka/integrations/BngStatsKafkaIntegrationTest.java
new file mode 100644
index 0000000..e05139c
--- /dev/null
+++ b/src/test/java/org/opencord/kafka/integrations/BngStatsKafkaIntegrationTest.java
@@ -0,0 +1,103 @@
+/*
+ * 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.integrations;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.onosproject.net.behaviour.BngProgrammable;
+import org.onosproject.net.pi.runtime.PiCounterCellData;
+import org.opencord.bng.BngStatsEventListener;
+import org.opencord.bng.BngStatsService;
+import org.opencord.kafka.EventBusService;
+
+import java.util.Map;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * set of unit test cases to verify BngStatsKafkaIntegration.
+ */
+class BngStatsKafkaIntegrationTest extends KafkaIntegrationTestBase {
+
+
+    private BngStatsKafkaIntegration bngStatsKafkaIntegration;
+    private BngStatsEventListener bngStatsEventListener;
+
+    @BeforeEach
+    void setUp() {
+        bngStatsKafkaIntegration = new BngStatsKafkaIntegration();
+        bngStatsKafkaIntegration.eventBusService = new MockEventBusService();
+        bngStatsKafkaIntegration.ignore = new MockBngStatsService();
+        bngStatsKafkaIntegration.bindBngStatsService(bngStatsKafkaIntegration.ignore);
+        bngStatsKafkaIntegration.activate();
+    }
+
+    @AfterEach
+    void tearDown() {
+        bngStatsKafkaIntegration.deactivate();
+    }
+
+    @Test
+    void testBngStatsEvent() {
+        bngStatsEventListener.event(getBngStatsEvent());
+        assertEquals(MockEventBusService.kafkaEvents, 1);
+        assertEquals(MockEventBusService.otherCounter, 0);
+    }
+
+    private static class MockEventBusService implements EventBusService {
+        static int kafkaEvents;
+        static int otherCounter;
+
+        MockEventBusService() {
+            kafkaEvents = 0;
+            otherCounter = 0;
+        }
+
+        @Override
+        public void send(String topic, JsonNode data) {
+            if (topic.equals(BngStatsKafkaIntegration.TOPIC_STATS)) {
+                kafkaEvents++;
+            } else {
+                otherCounter++;
+            }
+        }
+    }
+
+    private class MockBngStatsService implements BngStatsService {
+        @Override
+        public Map<BngProgrammable.BngCounterType, PiCounterCellData> getStats(String s) {
+            return null;
+        }
+
+        @Override
+        public PiCounterCellData getControlStats() {
+            return null;
+        }
+
+        @Override
+        public void addListener(BngStatsEventListener listener) {
+            bngStatsEventListener = listener;
+        }
+
+        @Override
+        public void removeListener(BngStatsEventListener listener) {
+            bngStatsEventListener = null;
+        }
+    }
+}
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