@Test public void testWritable() throws Exception { IntPairWritable one = new IntPairWritable(1,2); IntPairWritable two = new IntPairWritable(3,4); assertEquals(1, one.getFirst()); assertEquals(2, one.getSecond()); assertEquals(3, two.getFirst()); assertEquals(4, two.getSecond()); ByteArrayOutputStream bout = new ByteArrayOutputStream(); DataOutput out = new DataOutputStream(bout); two.write(out); byte[] b = bout.toByteArray(); ByteArrayInputStream bin = new ByteArrayInputStream(b); DataInput din = new DataInputStream(bin); one.readFields(din); assertEquals(two.getFirst(), one.getFirst()); assertEquals(two.getSecond(), one.getSecond()); }