Added unit test utilities and some more unit tests.
diff --git a/utils/junit/src/main/java/org/onlab/junit/TestTools.java b/utils/junit/src/main/java/org/onlab/junit/TestTools.java
new file mode 100644
index 0000000..959d5d9
--- /dev/null
+++ b/utils/junit/src/main/java/org/onlab/junit/TestTools.java
@@ -0,0 +1,93 @@
+package org.onlab.junit;
+
+import static com.google.common.base.Preconditions.checkArgument;
+import static org.junit.Assert.fail;
+
+/**
+ * Utilities to aid in producing JUnit tests.
+ */
+public final class TestTools {
+
+ // Prohibit construction
+ private TestTools() {
+ }
+
+ /**
+ * Suspends the current thread for a specified number of millis.
+ *
+ * @param ms number of millis
+ */
+ public static void delay(int ms) {
+ try {
+ Thread.sleep(ms);
+ } catch (InterruptedException e) {
+ fail("test interrupted");
+ }
+ }
+
+ /**
+ * Returns the current time in millis since epoch.
+ *
+ * @return current time
+ */
+ public static long now() {
+ return System.currentTimeMillis();
+ }
+
+ /**
+ * Runs the specified runnable until it completes successfully or until the
+ * specified time expires. If the latter occurs, the first encountered
+ * assertion on the last attempt will be re-thrown. Errors other than
+ * assertion errors will be propagated immediately.
+ * <p>
+ * Assertions attempts will not be closer than 10 millis apart and no
+ * further than 50 millis.
+ * </p>
+ *
+ * @param delay number of millis to delay before the first attempt
+ * @param duration number of milliseconds beyond the current time
+ * @param assertions test assertions runnable
+ */
+ public static void assertAfter(int delay, int duration, Runnable assertions) {
+ checkArgument(delay < duration, "delay >= duration");
+ long start = now();
+ int step = Math.max(Math.min((duration - delay) / 100, 50), 10);
+
+ // Is there an initial delay?
+ if (delay > 0) {
+ delay(delay);
+ }
+
+ // Keep going until the assertions succeed or until time runs-out.
+ while (true) {
+ try {
+ assertions.run();
+ break;
+ } catch (AssertionError e) {
+ // If there was an error and time ran out, re-throw it.
+ if (now() - start > duration) {
+ throw e;
+ }
+ }
+ delay(step);
+ }
+ }
+
+ /**
+ * Runs the specified runnable until it completes successfully or until the
+ * specified time expires. If the latter occurs, the first encountered
+ * assertion on the last attempt will be re-thrown. Errors other than
+ * assertion errors will be propagated immediately.
+ * <p>
+ * Assertions attempts will not be closer than 10 millis apart and no
+ * further than 50 millis.
+ * </p>
+ *
+ * @param duration number of milliseconds beyond the current time
+ * @param assertions test assertions runnable
+ */
+ public static void assertAfter(int duration, Runnable assertions) {
+ assertAfter(0, duration, assertions);
+ }
+
+}