Added unit test utilities and some more unit tests.
diff --git a/utils/junit/src/test/java/org/onlab/junit/TestToolsTest.java b/utils/junit/src/test/java/org/onlab/junit/TestToolsTest.java
new file mode 100644
index 0000000..9afc913
--- /dev/null
+++ b/utils/junit/src/test/java/org/onlab/junit/TestToolsTest.java
@@ -0,0 +1,32 @@
+package org.onlab.junit;
+
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+import static org.onlab.junit.TestTools.assertAfter;
+
+public class TestToolsTest {
+
+    @Test
+    public void testSuccess() {
+        assertAfter(10, 100, new Runnable() {
+            int count = 0;
+            @Override
+            public void run() {
+                if (count++ < 3) {
+                    assertTrue(false);
+                }
+            }
+        });
+    }
+
+    @Test(expected = AssertionError.class)
+    public void testFailure() {
+        assertAfter(100, new Runnable() {
+            @Override
+            public void run() {
+                assertTrue(false);
+            }
+        });
+    }
+}