/**
 * 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.hive.ql.udf;

import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;

import junit.framework.TestCase;

import java.util.TimeZone;

/**
 * JUnit test for UDFDateDiff.
 */
public class TestUDFDateDiff extends TestCase {

    /**
     * Verify differences of dates crossing a daylight savings time change
     * are correct.  The timezone tested is west coast US (PDT/PST) with a 
     * 1 hour shift back in time at 02:00 AM on 2009-10-31 and a
     * 1 hour shift forward in time at 02:00 AM on 2010-03-14.
     */
    public void testDaylightChange() throws Exception {
        TimeZone.setDefault(TimeZone.getTimeZone("America/Los_Angeles"));

        // time moves ahead an hour at 02:00 on 2009-10-31
        // which results in a 23 hour long day
        Text date1 = new Text("2009-11-01");
        Text date2 = new Text("2009-10-25");

        IntWritable result = new UDFDateDiff().evaluate(date1, date2);
        assertEquals(7, result.get());

        result = new UDFDateDiff().evaluate(date2, date1);
        assertEquals(-7, result.get());


        // time moves back an hour at 02:00 on 2010-03-14
        // which results in a 25 hour long day
        date1 = new Text("2010-03-15");
        date2 = new Text("2010-03-08");

        result = new UDFDateDiff().evaluate(date1, date2);
        assertEquals(7, result.get());

        result = new UDFDateDiff().evaluate(date2, date1);
        assertEquals(-7, result.get());

    }
}