diff --git a/app/src/test/java/org/opencord/olt/impl/OltTest.java b/app/src/test/java/org/opencord/olt/impl/OltTest.java
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+++ b/app/src/test/java/org/opencord/olt/impl/OltTest.java
@@ -0,0 +1,204 @@
+/*
+ * Copyright 2016-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.olt.impl;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.Set;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import org.onlab.packet.ChassisId;
+import org.onlab.packet.Ip4Address;
+import org.onlab.packet.MacAddress;
+import org.onlab.packet.VlanId;
+import org.onosproject.net.AnnotationKeys;
+import org.onosproject.net.Annotations;
+import org.onosproject.net.ConnectPoint;
+import org.onosproject.net.DefaultAnnotations;
+import org.onosproject.net.DefaultDevice;
+import org.onosproject.net.Device;
+import org.onosproject.net.DeviceId;
+import org.onosproject.net.Element;
+import org.onosproject.net.Port;
+import org.onosproject.net.PortNumber;
+import org.onosproject.net.device.DeviceServiceAdapter;
+import org.onosproject.net.provider.ProviderId;
+import org.opencord.sadis.SubscriberAndDeviceInformation;
+import org.opencord.sadis.SubscriberAndDeviceInformationService;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class OltTest {
+    private final Logger log = LoggerFactory.getLogger(getClass());
+    private Olt olt;
+
+    private static final VlanId CLIENT_C_TAG = VlanId.vlanId((short) 999);
+    private static final VlanId CLIENT_S_TAG = VlanId.vlanId((short) 111);
+    private static final String CLIENT_NAS_PORT_ID = "PON 1/1";
+    private static final String CLIENT_CIRCUIT_ID = "CIR-PON 1/1";
+
+    private static final String OLT_DEV_ID = "of:00000000000000aa";
+    private static final DeviceId DEVICE_ID_1 = DeviceId.deviceId(OLT_DEV_ID);
+    private static final String SCHEME_NAME = "olt";
+    private static final DefaultAnnotations DEVICE_ANNOTATIONS = DefaultAnnotations.builder()
+            .set(AnnotationKeys.PROTOCOL, SCHEME_NAME.toUpperCase()).build();
+
+    @Before
+    public void setUp() {
+        olt = new Olt();
+        olt.deviceService = new MockDeviceService();
+        olt.subsService = new MockSubService();
+    }
+
+    /**
+     * Tests that the getSubscriber method does throw a NullPointerException with a meaningful message.
+     */
+    @Test
+    public void testGetSubscriberError() {
+        ConnectPoint cp = ConnectPoint.deviceConnectPoint(OLT_DEV_ID + "/" + 1);
+        try {
+            olt.getSubscriber(cp);
+        } catch (NullPointerException e) {
+            assertEquals(e.getMessage(), "Invalid connect point");
+        }
+    }
+
+    /**
+     * Tests that the getSubscriber method returns Subscriber informations.
+     */
+    @Test
+    public void testGetSubscriber() {
+        ConnectPoint cp = ConnectPoint.deviceConnectPoint(OLT_DEV_ID + "/" + 2);
+
+        SubscriberAndDeviceInformation s =  olt.getSubscriber(cp);
+
+        assertEquals(s.circuitId(), CLIENT_CIRCUIT_ID);
+        assertEquals(s.cTag(), CLIENT_C_TAG);
+        assertEquals(s.sTag(), CLIENT_S_TAG);
+        assertEquals(s.nasPortId(), CLIENT_NAS_PORT_ID);
+    }
+
+    private class MockDevice extends DefaultDevice {
+
+        public MockDevice(ProviderId providerId, DeviceId id, Type type,
+                          String manufacturer, String hwVersion, String swVersion,
+                          String serialNumber, ChassisId chassisId, Annotations... annotations) {
+            super(providerId, id, type, manufacturer, hwVersion, swVersion, serialNumber,
+                  chassisId, annotations);
+        }
+    }
+
+    private class MockDeviceService extends DeviceServiceAdapter {
+
+        private ProviderId providerId = new ProviderId("of", "foo");
+        private final Device device1 = new MockDevice(providerId, DEVICE_ID_1, Device.Type.SWITCH,
+                                                      "foo.inc", "0", "0", OLT_DEV_ID, new ChassisId(),
+                                                      DEVICE_ANNOTATIONS);
+
+        @Override
+        public Device getDevice(DeviceId devId) {
+            return device1;
+
+        }
+
+        @Override
+        public Port getPort(ConnectPoint cp) {
+            log.info("Looking up port {}", cp.port().toString());
+            if (cp.port().toString().equals("1")) {
+                return null;
+            }
+            return new MockPort();
+        }
+    }
+
+    private class  MockPort implements Port {
+
+        @Override
+        public boolean isEnabled() {
+            return true;
+        }
+        @Override
+        public long portSpeed() {
+            return 1000;
+        }
+        @Override
+        public Element element() {
+            return null;
+        }
+        @Override
+        public PortNumber number() {
+            return null;
+        }
+        @Override
+        public Annotations annotations() {
+            return new MockAnnotations();
+        }
+        @Override
+        public Type type() {
+            return Port.Type.FIBER;
+        }
+
+        private class MockAnnotations implements Annotations {
+
+            @Override
+            public String value(String val) {
+                return "BRCM12345678";
+            }
+            @Override
+            public Set<String> keys() {
+                return null;
+            }
+        }
+    }
+
+    private class MockSubService implements SubscriberAndDeviceInformationService {
+        MockSubscriberAndDeviceInformation sub =
+                new MockSubscriberAndDeviceInformation(CLIENT_NAS_PORT_ID, CLIENT_C_TAG,
+                                                       CLIENT_S_TAG, CLIENT_NAS_PORT_ID, CLIENT_CIRCUIT_ID, null, null);
+        @Override
+        public SubscriberAndDeviceInformation get(String id) {
+            return  sub;
+        }
+
+        @Override
+        public void invalidateAll() {}
+        @Override
+        public void invalidateId(String id) {}
+        @Override
+        public SubscriberAndDeviceInformation getfromCache(String id) {
+            return null;
+        }
+    }
+
+    private class MockSubscriberAndDeviceInformation extends SubscriberAndDeviceInformation {
+
+        MockSubscriberAndDeviceInformation(String id, VlanId ctag,
+                                           VlanId stag, String nasPortId,
+                                           String circuitId, MacAddress hardId,
+                                           Ip4Address ipAddress) {
+            this.setCTag(ctag);
+            this.setHardwareIdentifier(hardId);
+            this.setId(id);
+            this.setIPAddress(ipAddress);
+            this.setSTag(stag);
+            this.setNasPortId(nasPortId);
+            this.setCircuitId(circuitId);
+        }
+    }
+
+}
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