private void compareToUDFHourLong(Timestamp t, int y) throws HiveException {
    UDFHour udf = new UDFHour();
    udf.initialize(new ObjectInspector[]{PrimitiveObjectInspectorFactory.writableTimestampObjectInspector});
    TimestampWritableV2 tsw = new TimestampWritableV2(
        org.apache.hadoop.hive.common.type.Timestamp.ofEpochMilli(t.getTime(), t.getNanos()));
    IntWritable res = (IntWritable) udf.evaluate(
        new GenericUDF.DeferredObject[]{new GenericUDF.DeferredJavaObject(tsw)});
    Assert.assertEquals(res.get(), y);
  }
Input array is used to fill the entire size of the vector row batch
ql/src/test/org/apache/hadoop/hive/ql/exec/vector/expressions/TestVectorTimestampExpressions.java