diff --git a/core/trivial/src/main/java/org/onlab/onos/net/trivial/device/impl/SimpleDeviceManager.java b/core/trivial/src/main/java/org/onlab/onos/net/trivial/device/impl/SimpleDeviceManager.java
index 221a249..d037f2a 100644
--- a/core/trivial/src/main/java/org/onlab/onos/net/trivial/device/impl/SimpleDeviceManager.java
+++ b/core/trivial/src/main/java/org/onlab/onos/net/trivial/device/impl/SimpleDeviceManager.java
@@ -48,7 +48,7 @@
 
     private final Logger log = getLogger(getClass());
 
-    private final AbstractListenerRegistry<DeviceEvent, DeviceListener>
+    protected final AbstractListenerRegistry<DeviceEvent, DeviceListener>
             listenerRegistry = new AbstractListenerRegistry<>();
 
     private final SimpleDeviceStore store = new SimpleDeviceStore();
diff --git a/core/trivial/src/main/java/org/onlab/onos/net/trivial/link/impl/SimpleLinkManager.java b/core/trivial/src/main/java/org/onlab/onos/net/trivial/link/impl/SimpleLinkManager.java
index a817bb6..4ea1753 100644
--- a/core/trivial/src/main/java/org/onlab/onos/net/trivial/link/impl/SimpleLinkManager.java
+++ b/core/trivial/src/main/java/org/onlab/onos/net/trivial/link/impl/SimpleLinkManager.java
@@ -45,7 +45,7 @@
 
     private final Logger log = getLogger(getClass());
 
-    private final AbstractListenerRegistry<LinkEvent, LinkListener>
+    protected final AbstractListenerRegistry<LinkEvent, LinkListener>
             listenerRegistry = new AbstractListenerRegistry<>();
 
     private final SimpleLinkStore store = new SimpleLinkStore();
diff --git a/core/trivial/src/test/java/org/onlab/onos/net/trivial/topology/impl/DefaultTopologyProviderTest.java b/core/trivial/src/test/java/org/onlab/onos/net/trivial/topology/impl/DefaultTopologyProviderTest.java
new file mode 100644
index 0000000..2312996
--- /dev/null
+++ b/core/trivial/src/test/java/org/onlab/onos/net/trivial/topology/impl/DefaultTopologyProviderTest.java
@@ -0,0 +1,162 @@
+package org.onlab.onos.net.trivial.topology.impl;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.onlab.onos.event.Event;
+import org.onlab.onos.event.impl.TestEventDispatcher;
+import org.onlab.onos.net.Device;
+import org.onlab.onos.net.Link;
+import org.onlab.onos.net.device.DeviceEvent;
+import org.onlab.onos.net.link.LinkEvent;
+import org.onlab.onos.net.provider.AbstractProviderService;
+import org.onlab.onos.net.provider.ProviderId;
+import org.onlab.onos.net.topology.GraphDescription;
+import org.onlab.onos.net.topology.TopologyProvider;
+import org.onlab.onos.net.topology.TopologyProviderRegistry;
+import org.onlab.onos.net.topology.TopologyProviderService;
+import org.onlab.onos.net.trivial.device.impl.SimpleDeviceManager;
+import org.onlab.onos.net.trivial.link.impl.SimpleLinkManager;
+
+import java.util.List;
+import java.util.Set;
+
+import static com.google.common.collect.ImmutableSet.of;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.onlab.junit.TestTools.assertAfter;
+import static org.onlab.onos.net.device.DeviceEvent.Type.DEVICE_ADDED;
+import static org.onlab.onos.net.link.LinkEvent.Type.LINK_ADDED;
+import static org.onlab.onos.net.trivial.topology.impl.SimpleTopologyManagerTest.device;
+import static org.onlab.onos.net.trivial.topology.impl.SimpleTopologyManagerTest.link;
+
+/**
+ * Test of the default topology provider implementation.
+ */
+public class DefaultTopologyProviderTest {
+
+    private DefaultTopologyProvider provider = new DefaultTopologyProvider();
+    private TestTopoRegistry topologyService = new TestTopoRegistry();
+    private TestDeviceService deviceService = new TestDeviceService();
+    private TestLinkService linkService = new TestLinkService();
+    private TestTopoProviderService providerService;
+
+    @Before
+    public void setUp() {
+        provider.deviceService = deviceService;
+        provider.linkService = linkService;
+        provider.providerRegistry = topologyService;
+        provider.activate();
+    }
+
+    @After
+    public void tearDown() {
+        provider.deactivate();
+        provider.providerRegistry = null;
+        provider.deviceService = null;
+        provider.linkService = null;
+    }
+
+    private void validateSubmission() {
+        assertNotNull("registration expected", providerService);
+        assertEquals("incorrect providert", provider, providerService.provider());
+        assertNotNull("topo change should be submitted", providerService.graphDesc);
+        assertEquals("incorrect vertex count", 6, providerService.graphDesc.vertexes().size());
+        assertEquals("incorrect edge count", 10, providerService.graphDesc.edges().size());
+    }
+
+    @Test
+    public void basics() {
+        assertAfter(100, new Runnable() {
+            @Override
+            public void run() {
+                validateSubmission();
+            }
+        });
+    }
+
+    @Test
+    public void eventDriven() {
+        assertAfter(100, new Runnable() {
+            @Override
+            public void run() {
+                validateSubmission();
+                deviceService.post(new DeviceEvent(DEVICE_ADDED, device("z"), null));
+                linkService.post(new LinkEvent(LINK_ADDED, link("z", 1, "a", 4)));
+                validateSubmission();
+            }
+        });
+    }
+
+
+    private class TestTopoRegistry implements TopologyProviderRegistry {
+
+        @Override
+        public TopologyProviderService register(TopologyProvider provider) {
+            providerService = new TestTopoProviderService(provider);
+            return providerService;
+        }
+
+        @Override
+        public void unregister(TopologyProvider provider) {
+        }
+
+        @Override
+        public Set<ProviderId> getProviders() {
+            return null;
+        }
+    }
+
+    private class TestTopoProviderService
+            extends AbstractProviderService<TopologyProvider>
+            implements TopologyProviderService {
+        GraphDescription graphDesc;
+
+        protected TestTopoProviderService(TopologyProvider provider) {
+            super(provider);
+        }
+
+        @Override
+        public void topologyChanged(GraphDescription graphDescription, List<Event> reasons) {
+            graphDesc = graphDescription;
+        }
+    }
+
+    private class TestDeviceService extends SimpleDeviceManager {
+        TestDeviceService() {
+            eventDispatcher = new TestEventDispatcher();
+            eventDispatcher.addSink(DeviceEvent.class, listenerRegistry);
+        }
+
+        @Override
+        public Iterable<Device> getDevices() {
+            return of(device("a"), device("b"),
+                      device("c"), device("d"),
+                      device("e"), device("f"));
+        }
+
+        void post(DeviceEvent event) {
+            eventDispatcher.post(event);
+        }
+    }
+
+    private class TestLinkService extends SimpleLinkManager {
+        TestLinkService() {
+            eventDispatcher = new TestEventDispatcher();
+            eventDispatcher.addSink(LinkEvent.class, listenerRegistry);
+        }
+
+        @Override
+        public Iterable<Link> getLinks() {
+            return of(link("a", 1, "b", 1), link("b", 1, "a", 1),
+                      link("b", 2, "c", 1), link("c", 1, "b", 2),
+                      link("c", 2, "d", 1), link("d", 1, "c", 2),
+                      link("d", 2, "a", 2), link("a", 2, "d", 2),
+                      link("e", 1, "f", 1), link("f", 1, "e", 1));
+        }
+
+        void post(LinkEvent event) {
+            eventDispatcher.post(event);
+        }
+    }
+}
\ No newline at end of file
diff --git a/core/trivial/src/test/java/org/onlab/onos/net/trivial/topology/impl/SimpleTopologyManagerTest.java b/core/trivial/src/test/java/org/onlab/onos/net/trivial/topology/impl/SimpleTopologyManagerTest.java
index a595cbe..1480cec 100644
--- a/core/trivial/src/test/java/org/onlab/onos/net/trivial/topology/impl/SimpleTopologyManagerTest.java
+++ b/core/trivial/src/test/java/org/onlab/onos/net/trivial/topology/impl/SimpleTopologyManagerTest.java
@@ -182,20 +182,20 @@
     }
 
     // Short-hand for creating a link.
-    private Link link(String src, int sp, String dst, int dp) {
+    static Link link(String src, int sp, String dst, int dp) {
         return new DefaultLink(PID, new ConnectPoint(did(src), portNumber(sp)),
                                new ConnectPoint(did(dst), portNumber(dp)),
                                Link.Type.DIRECT);
     }
 
     // Crates a new device with the specified id
-    private Device device(String id) {
+    static Device device(String id) {
         return new DefaultDevice(PID, did(id), Device.Type.SWITCH,
                                  "mfg", "1.0", "1.1", "1234");
     }
 
     // Short-hand for producing a device id from a string
-    private DeviceId did(String id) {
+    static DeviceId did(String id) {
         return deviceId("of:" + id);
     }