diff --git a/core/api/src/test/java/org/onlab/onos/net/DefaultAnnotationsTest.java b/core/api/src/test/java/org/onlab/onos/net/DefaultAnnotationsTest.java
new file mode 100644
index 0000000..274f4b8
--- /dev/null
+++ b/core/api/src/test/java/org/onlab/onos/net/DefaultAnnotationsTest.java
@@ -0,0 +1,68 @@
+package org.onlab.onos.net;
+
+import org.junit.Test;
+
+import static com.google.common.collect.ImmutableSet.of;
+import static org.junit.Assert.*;
+import static org.onlab.onos.net.DefaultAnnotations.builder;
+
+/**
+ * Tests of the default annotations.
+ */
+public class DefaultAnnotationsTest {
+
+    private DefaultAnnotations annotations;
+
+    @Test
+    public void basics() {
+        annotations = builder().set("foo", "1").set("bar", "2").build();
+        assertEquals("incorrect keys", of("foo", "bar"), annotations.keys());
+        assertEquals("incorrect value", "1", annotations.value("foo"));
+        assertEquals("incorrect value", "2", annotations.value("bar"));
+    }
+
+    @Test
+    public void empty() {
+        annotations = builder().build();
+        assertTrue("incorrect keys", annotations.keys().isEmpty());
+    }
+
+    @Test
+    public void remove() {
+        annotations = builder().remove("foo").set("bar", "2").build();
+        assertEquals("incorrect keys", of("foo", "bar"), annotations.keys());
+        assertNull("incorrect value", annotations.value("foo"));
+        assertEquals("incorrect value", "2", annotations.value("bar"));
+    }
+
+    @Test
+    public void merge() {
+        annotations = builder().set("foo", "1").set("bar", "2").build();
+        assertEquals("incorrect keys", of("foo", "bar"), annotations.keys());
+
+        SparseAnnotations updates = builder().remove("foo").set("bar", "3").set("goo", "4").build();
+
+        annotations = DefaultAnnotations.merge(annotations, updates);
+        assertEquals("incorrect keys", of("goo", "bar"), annotations.keys());
+        assertNull("incorrect value", annotations.value("foo"));
+        assertEquals("incorrect value", "3", annotations.value("bar"));
+    }
+
+    @Test
+    public void noopMerge() {
+        annotations = builder().set("foo", "1").set("bar", "2").build();
+        assertEquals("incorrect keys", of("foo", "bar"), annotations.keys());
+
+        SparseAnnotations updates = builder().build();
+        assertSame("same annotations expected", annotations,
+                   DefaultAnnotations.merge(annotations, updates));
+        assertSame("same annotations expected", annotations,
+                   DefaultAnnotations.merge(annotations, null));
+    }
+
+    @Test(expected = NullPointerException.class)
+    public void badMerge() {
+        DefaultAnnotations.merge(null, null);
+    }
+
+}
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