HADOOP-4297. Enable Java assertions when running tests. Contributed by Tsz Wo Nicholas Sze.

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -502,6 +502,9 @@ Release 2.7.0 - UNRELEASED
     HADOOP-11450. Cleanup DistCpV1 not to use deprecated methods and fix
     javadocs. (Varun Saxena via ozawa)
 
+    HADOOP-4297. Enable Java assertions when running tests.
+    (Tsz Wo Nicholas Sze via wheat9)
+
   OPTIMIZATIONS
 
     HADOOP-11323. WritableComparator#compare keeps reference to byte array.

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/test/TestJUnitSetup.java

@@ -0,0 +1,39 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.apache.hadoop.test;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class TestJUnitSetup {
+  public static final Log LOG = LogFactory.getLog(TestJUnitSetup.class);
+
+  @Test
+  public void testJavaAssert() {
+    try {
+      assert false : "Good! Java assert is on.";
+    } catch(AssertionError ae) {
+      LOG.info("The AssertionError is expected.", ae);
+      return;
+    }
+    Assert.fail("Java assert does not work.");
+  }
+}