/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-present, by David Gilbert and Contributors.
 *
 * Project Info:  http://www.jfree.org/jfreechart/index.html
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
 * USA.
 *
 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. 
 * Other names may be trademarks of their respective owners.]
 *
 * -----------------
 * DateAxisTest.java
 * -----------------
 * (C) Copyright 2003-present, by David Gilbert and Contributors.
 *
 * Original Author:  David Gilbert;
 * Contributor(s):   -;
 *
 */

package org.jfree.chart.axis;

import org.junit.jupiter.api.Test;

import java.awt.Graphics2D;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.List;
import java.util.Locale;
import java.util.TimeZone;

import org.jfree.chart.TestUtils;
import org.jfree.chart.ui.RectangleEdge;

import org.jfree.data.time.DateRange;
import org.jfree.data.time.Day;
import org.jfree.data.time.Hour;
import org.jfree.data.time.Millisecond;
import org.jfree.data.time.Minute;
import org.jfree.data.time.Month;
import org.jfree.data.time.Second;
import org.jfree.data.time.Year;

import static org.junit.jupiter.api.Assertions.*;

/**
 * Tests for the {@link DateAxis} class.
 */
public class DateAxisTest {

    static class MyDateAxis extends DateAxis {

        /**
         * Creates a new instance.
         *
         * @param label  the label.
         */
        public MyDateAxis(String label) {
            super(label);
        }

        @Override
        public Date previousStandardDate(Date d, DateTickUnit unit) {
            return super.previousStandardDate(d, unit);
        }
    }

    /**
     * Confirm that the equals method can distinguish all the required fields.
     */
    @Test
    public void testEquals() {

        DateAxis a1 = new DateAxis("Test");
        DateAxis a2 = new DateAxis("Test");
        assertEquals(a1, a2);
        assertNotEquals(null, a1);
        assertNotEquals("Some non-DateAxis object", a1);

        a1 = new DateAxis("Test", TimeZone.getTimeZone("PST"), Locale.US);
        assertNotEquals(a1, a2);
        a2 = new DateAxis("Test", TimeZone.getTimeZone("PST"), Locale.US);
        assertEquals(a1, a2);
        
        a1 = new DateAxis("Test", TimeZone.getTimeZone("PST"), Locale.FRANCE);
        assertNotEquals(a1, a2);
        a2 = new DateAxis("Test", TimeZone.getTimeZone("PST"), Locale.FRANCE);
        assertEquals(a1, a2);

        // tickUnit
        a1.setTickUnit(new DateTickUnit(DateTickUnitType.DAY, 7));
        assertNotEquals(a1, a2);
        a2.setTickUnit(new DateTickUnit(DateTickUnitType.DAY, 7));
        assertEquals(a1, a2);

        // dateFormatOverride
        a1.setDateFormatOverride(new SimpleDateFormat("yyyy"));
        assertNotEquals(a1, a2);
        a2.setDateFormatOverride(new SimpleDateFormat("yyyy"));
        assertEquals(a1, a2);

        // tickMarkPosition
        a1.setTickMarkPosition(DateTickMarkPosition.END);
        assertNotEquals(a1, a2);
        a2.setTickMarkPosition(DateTickMarkPosition.END);
        assertEquals(a1, a2);

    }

    /**
     * A test for bug report 1472942.  The DateFormat.equals() method is not
     * checking the range attribute.
     */
    @Test
    public void test1472942() {
        DateAxis a1 = new DateAxis("Test");
        DateAxis a2 = new DateAxis("Test");
        assertEquals(a1, a2);

        // range
        a1.setRange(new Date(1L), new Date(2L));
        assertNotEquals(a1, a2);
        a2.setRange(new Date(1L), new Date(2L));
        assertEquals(a1, a2);
    }

    /**
     * Two objects that are equal are required to return the same hashCode.
     */
    @Test
    public void testHashCode() {
        DateAxis a1 = new DateAxis("Test");
        DateAxis a2 = new DateAxis("Test");
        assertEquals(a1, a2);
        int h1 = a1.hashCode();
        int h2 = a2.hashCode();
        assertEquals(h1, h2);
    }

    /**
     * Confirm that cloning works.
     */
    @Test
    public void testCloning() throws CloneNotSupportedException {
        DateAxis a1 = new DateAxis("Test");
        DateAxis a2 = (DateAxis) a1.clone();
        assertNotSame(a1, a2);
        assertSame(a1.getClass(), a2.getClass());
        assertEquals(a1, a2);
    }

    /**
     * Test that the setRange() method works.
     */
    @Test
    public void testSetRange() {

        DateAxis axis = new DateAxis("Test Axis");
        Calendar calendar = Calendar.getInstance();
        calendar.set(1999, Calendar.JANUARY, 3);
        Date d1 = calendar.getTime();
        calendar.set(1999, Calendar.JANUARY, 31);
        Date d2 = calendar.getTime();
        axis.setRange(d1, d2);

        DateRange range = (DateRange) axis.getRange();
        assertEquals(d1, range.getLowerDate());
        assertEquals(d2, range.getUpperDate());

    }

    /**
     * Test that the setMaximumDate() method works.
     */
    @Test
    public void testSetMaximumDate() {
        DateAxis axis = new DateAxis("Test Axis");
        Date date = new Date();
        axis.setMaximumDate(date);
        assertEquals(date, axis.getMaximumDate());

        // check that setting the max date to something on or before the
        // current min date works...
        Date d1 = new Date();
        Date d2 = new Date(d1.getTime() + 1);
        Date d0 = new Date(d1.getTime() - 1);
        axis.setMaximumDate(d2);
        axis.setMinimumDate(d1);
        axis.setMaximumDate(d1);
        assertEquals(d0, axis.getMinimumDate());
    }

    /**
     * Test that the setMinimumDate() method works.
     */
    @Test
    public void testSetMinimumDate() {
        DateAxis axis = new DateAxis("Test Axis");
        Date d1 = new Date();
        Date d2 = new Date(d1.getTime() + 1);
        axis.setMaximumDate(d2);
        axis.setMinimumDate(d1);
        assertEquals(d1, axis.getMinimumDate());

        // check that setting the min date to something on or after the
        // current min date works...
        Date d3 = new Date(d2.getTime() + 1);
        axis.setMinimumDate(d2);
        assertEquals(d3, axis.getMaximumDate());
    }

    /**
     * Tests two doubles for 'near enough' equality.
     *
     * @param d1  number 1.
     * @param d2  number 2.
     * @param tolerance  maximum tolerance.
     *
     * @return A boolean.
     */
    private boolean same(double d1, double d2, double tolerance) {
        return (Math.abs(d1 - d2) < tolerance);
    }

    /**
     * Test the translation of Java2D values to data values.
     */
    @Test
    public void testJava2DToValue() {
        DateAxis axis = new DateAxis();
        axis.setRange(50.0, 100.0);
        Rectangle2D dataArea = new Rectangle2D.Double(10.0, 50.0, 400.0, 300.0);
        double y1 = axis.java2DToValue(75.0, dataArea, RectangleEdge.LEFT);
        assertTrue(same(y1, 95.8333333, 1.0));
        double y2 = axis.java2DToValue(75.0, dataArea, RectangleEdge.RIGHT);
        assertTrue(same(y2, 95.8333333, 1.0));
        double x1 = axis.java2DToValue(75.0, dataArea, RectangleEdge.TOP);
        assertTrue(same(x1, 58.125, 1.0));
        double x2 = axis.java2DToValue(75.0, dataArea, RectangleEdge.BOTTOM);
        assertTrue(same(x2, 58.125, 1.0));
        axis.setInverted(true);
        double y3 = axis.java2DToValue(75.0, dataArea, RectangleEdge.LEFT);
        assertTrue(same(y3, 54.1666667, 1.0));
        double y4 = axis.java2DToValue(75.0, dataArea, RectangleEdge.RIGHT);
        assertTrue(same(y4, 54.1666667, 1.0));
        double x3 = axis.java2DToValue(75.0, dataArea, RectangleEdge.TOP);
        assertTrue(same(x3, 91.875, 1.0));
        double x4 = axis.java2DToValue(75.0, dataArea, RectangleEdge.BOTTOM);
        assertTrue(same(x4, 91.875, 1.0));
    }

    /**
     * Serialize an instance, restore it, and check for equality.
     */
    @Test
    public void testSerialization() {
        DateAxis a1 = new DateAxis("Test Axis");
        DateAxis a2 = TestUtils.serialised(a1);
        assertEquals(a1, a2);
    }

    /**
     * A basic check for the testPreviousStandardDate() method when the
     * tick unit is 1 year.
     */
    @Test
    public void testPreviousStandardDateYearA() {
        MyDateAxis axis = new MyDateAxis("Year");
        Year y2006 = new Year(2006);
        Year y2007 = new Year(2007);

        // five dates to check...
        Date d0 = new Date(y2006.getFirstMillisecond());
        Date d1 = new Date(y2006.getFirstMillisecond() + 500L);
        Date d2 = new Date(y2006.getMiddleMillisecond());
        Date d3 = new Date(y2006.getMiddleMillisecond() + 500L);
        Date d4 = new Date(y2006.getLastMillisecond());

        Date end = new Date(y2007.getLastMillisecond());

        DateTickUnit unit = new DateTickUnit(DateTickUnitType.YEAR, 1);
        axis.setTickUnit(unit);

        // START: check d0 and d1
        axis.setTickMarkPosition(DateTickMarkPosition.START);

        axis.setRange(d0, end);
        Date psd = axis.previousStandardDate(d0, unit);
        Date nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d0.getTime());
        assertTrue(nsd.getTime() >= d0.getTime());

        axis.setRange(d1, end);
        psd = axis.previousStandardDate(d1, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d1.getTime());
        assertTrue(nsd.getTime() >= d1.getTime());

        // MIDDLE: check d1, d2 and d3
        axis.setTickMarkPosition(DateTickMarkPosition.MIDDLE);

        axis.setRange(d1, end);
        psd = axis.previousStandardDate(d1, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d1.getTime());
        assertTrue(nsd.getTime() >= d1.getTime());

        axis.setRange(d2, end);
        psd = axis.previousStandardDate(d2, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d2.getTime());
        assertTrue(nsd.getTime() >= d2.getTime());

        axis.setRange(d3, end);
        psd = axis.previousStandardDate(d3, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d3.getTime());
        assertTrue(nsd.getTime() >= d3.getTime());

        // END: check d3 and d4
        axis.setTickMarkPosition(DateTickMarkPosition.END);

        axis.setRange(d3, end);
        psd = axis.previousStandardDate(d3, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d3.getTime());
        assertTrue(nsd.getTime() >= d3.getTime());

        axis.setRange(d4, end);
        psd = axis.previousStandardDate(d4, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d4.getTime());
        assertTrue(nsd.getTime() >= d4.getTime());
    }

    /**
     * A basic check for the testPreviousStandardDate() method when the
     * tick unit is 10 years (just for the sake of having a multiple).
     */
    @Test
    public void testPreviousStandardDateYearB() {
        MyDateAxis axis = new MyDateAxis("Year");
        Year y2006 = new Year(2006);
        Year y2007 = new Year(2007);

        // five dates to check...
        Date d0 = new Date(y2006.getFirstMillisecond());
        Date d1 = new Date(y2006.getFirstMillisecond() + 500L);
        Date d2 = new Date(y2006.getMiddleMillisecond());
        Date d3 = new Date(y2006.getMiddleMillisecond() + 500L);
        Date d4 = new Date(y2006.getLastMillisecond());

        Date end = new Date(y2007.getLastMillisecond());

        DateTickUnit unit = new DateTickUnit(DateTickUnitType.YEAR, 10);
        axis.setTickUnit(unit);

        // START: check d0 and d1
        axis.setTickMarkPosition(DateTickMarkPosition.START);

        axis.setRange(d0, end);
        Date psd = axis.previousStandardDate(d0, unit);
        Date nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d0.getTime());
        assertTrue(nsd.getTime() >= d0.getTime());

        axis.setRange(d1, end);
        psd = axis.previousStandardDate(d1, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d1.getTime());
        assertTrue(nsd.getTime() >= d1.getTime());

        // MIDDLE: check d1, d2 and d3
        axis.setTickMarkPosition(DateTickMarkPosition.MIDDLE);

        axis.setRange(d1, end);
        psd = axis.previousStandardDate(d1, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d1.getTime());
        assertTrue(nsd.getTime() >= d1.getTime());

        axis.setRange(d2, end);
        psd = axis.previousStandardDate(d2, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d2.getTime());
        assertTrue(nsd.getTime() >= d2.getTime());

        axis.setRange(d3, end);
        psd = axis.previousStandardDate(d3, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d3.getTime());
        assertTrue(nsd.getTime() >= d3.getTime());

        // END: check d3 and d4
        axis.setTickMarkPosition(DateTickMarkPosition.END);

        axis.setRange(d3, end);
        psd = axis.previousStandardDate(d3, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d3.getTime());
        assertTrue(nsd.getTime() >= d3.getTime());

        axis.setRange(d4, end);
        psd = axis.previousStandardDate(d4, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d4.getTime());
        assertTrue(nsd.getTime() >= d4.getTime());
    }

    /**
     * A basic check for the testPreviousStandardDate() method when the
     * tick unit is 1 month.
     */
    @Test
    public void testPreviousStandardDateMonthA() {
        MyDateAxis axis = new MyDateAxis("Month");
        Month nov2006 = new Month(11, 2006);
        Month dec2006 = new Month(12, 2006);

        // five dates to check...
        Date d0 = new Date(nov2006.getFirstMillisecond());
        Date d1 = new Date(nov2006.getFirstMillisecond() + 500L);
        Date d2 = new Date(nov2006.getMiddleMillisecond());
        Date d3 = new Date(nov2006.getMiddleMillisecond() + 500L);
        Date d4 = new Date(nov2006.getLastMillisecond());

        Date end = new Date(dec2006.getLastMillisecond());

        DateTickUnit unit = new DateTickUnit(DateTickUnitType.MONTH, 1);
        axis.setTickUnit(unit);

        // START: check d0 and d1
        axis.setTickMarkPosition(DateTickMarkPosition.START);

        axis.setRange(d0, end);
        Date psd = axis.previousStandardDate(d0, unit);
        Date nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d0.getTime());
        assertTrue(nsd.getTime() >= d0.getTime());

        axis.setRange(d1, end);
        psd = axis.previousStandardDate(d1, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d1.getTime());
        assertTrue(nsd.getTime() >= d1.getTime());

        // MIDDLE: check d1, d2 and d3
        axis.setTickMarkPosition(DateTickMarkPosition.MIDDLE);

        axis.setRange(d1, end);
        psd = axis.previousStandardDate(d1, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d1.getTime());
        assertTrue(nsd.getTime() >= d1.getTime());

        axis.setRange(d2, end);
        psd = axis.previousStandardDate(d2, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d2.getTime());
        assertTrue(nsd.getTime() >= d2.getTime());

        axis.setRange(d3, end);
        psd = axis.previousStandardDate(d3, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d3.getTime());
        assertTrue(nsd.getTime() >= d3.getTime());

        // END: check d3 and d4
        axis.setTickMarkPosition(DateTickMarkPosition.END);

        axis.setRange(d3, end);
        psd = axis.previousStandardDate(d3, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d3.getTime());
        assertTrue(nsd.getTime() >= d3.getTime());

        axis.setRange(d4, end);
        psd = axis.previousStandardDate(d4, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d4.getTime());
        assertTrue(nsd.getTime() >= d4.getTime());
    }

    /**
     * A basic check for the testPreviousStandardDate() method when the
     * tick unit is 3 months (just for the sake of having a multiple).
     */
    @Test
    public void testPreviousStandardDateMonthB() {
        MyDateAxis axis = new MyDateAxis("Month");
        Month nov2006 = new Month(11, 2006);
        Month dec2006 = new Month(12, 2006);

        // five dates to check...
        Date d0 = new Date(nov2006.getFirstMillisecond());
        Date d1 = new Date(nov2006.getFirstMillisecond() + 500L);
        Date d2 = new Date(nov2006.getMiddleMillisecond());
        Date d3 = new Date(nov2006.getMiddleMillisecond() + 500L);
        Date d4 = new Date(nov2006.getLastMillisecond());

        Date end = new Date(dec2006.getLastMillisecond());

        DateTickUnit unit = new DateTickUnit(DateTickUnitType.MONTH, 3);
        axis.setTickUnit(unit);

        // START: check d0 and d1
        axis.setTickMarkPosition(DateTickMarkPosition.START);

        axis.setRange(d0, end);
        Date psd = axis.previousStandardDate(d0, unit);
        Date nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d0.getTime());
        assertTrue(nsd.getTime() >= d0.getTime());

        axis.setRange(d1, end);
        psd = axis.previousStandardDate(d1, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d1.getTime());
        assertTrue(nsd.getTime() >= d1.getTime());

        // MIDDLE: check d1, d2 and d3
        axis.setTickMarkPosition(DateTickMarkPosition.MIDDLE);

        axis.setRange(d1, end);
        psd = axis.previousStandardDate(d1, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d1.getTime());
        assertTrue(nsd.getTime() >= d1.getTime());

        axis.setRange(d2, end);
        psd = axis.previousStandardDate(d2, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d2.getTime());
        assertTrue(nsd.getTime() >= d2.getTime());

        axis.setRange(d3, end);
        psd = axis.previousStandardDate(d3, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d3.getTime());
        assertTrue(nsd.getTime() >= d3.getTime());

        // END: check d3 and d4
        axis.setTickMarkPosition(DateTickMarkPosition.END);

        axis.setRange(d3, end);
        psd = axis.previousStandardDate(d3, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d3.getTime());
        assertTrue(nsd.getTime() >= d3.getTime());

        axis.setRange(d4, end);
        psd = axis.previousStandardDate(d4, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d4.getTime());
        assertTrue(nsd.getTime() >= d4.getTime());
    }

    /**
     * A basic check for the testPreviousStandardDate() method when the
     * tick unit is 1 day.
     */
    @Test
    public void testPreviousStandardDateDayA() {
        MyDateAxis axis = new MyDateAxis("Day");
        Day apr12007 = new Day(1, 4, 2007);
        Day apr22007 = new Day(2, 4, 2007);

        // five dates to check...
        Date d0 = new Date(apr12007.getFirstMillisecond());
        Date d1 = new Date(apr12007.getFirstMillisecond() + 500L);
        Date d2 = new Date(apr12007.getMiddleMillisecond());
        Date d3 = new Date(apr12007.getMiddleMillisecond() + 500L);
        Date d4 = new Date(apr12007.getLastMillisecond());

        Date end = new Date(apr22007.getLastMillisecond());

        DateTickUnit unit = new DateTickUnit(DateTickUnitType.DAY, 1);
        axis.setTickUnit(unit);

        // START: check d0 and d1
        axis.setTickMarkPosition(DateTickMarkPosition.START);

        axis.setRange(d0, end);
        Date psd = axis.previousStandardDate(d0, unit);
        Date nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d0.getTime());
        assertTrue(nsd.getTime() >= d0.getTime());

        axis.setRange(d1, end);
        psd = axis.previousStandardDate(d1, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d1.getTime());
        assertTrue(nsd.getTime() >= d1.getTime());

        // MIDDLE: check d1, d2 and d3
        axis.setTickMarkPosition(DateTickMarkPosition.MIDDLE);

        axis.setRange(d1, end);
        psd = axis.previousStandardDate(d1, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d1.getTime());
        assertTrue(nsd.getTime() >= d1.getTime());

        axis.setRange(d2, end);
        psd = axis.previousStandardDate(d2, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d2.getTime());
        assertTrue(nsd.getTime() >= d2.getTime());

        axis.setRange(d3, end);
        psd = axis.previousStandardDate(d3, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d3.getTime());
        assertTrue(nsd.getTime() >= d3.getTime());

        // END: check d3 and d4
        axis.setTickMarkPosition(DateTickMarkPosition.END);

        axis.setRange(d3, end);
        psd = axis.previousStandardDate(d3, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d3.getTime());
        assertTrue(nsd.getTime() >= d3.getTime());

        axis.setRange(d4, end);
        psd = axis.previousStandardDate(d4, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d4.getTime());
        assertTrue(nsd.getTime() >= d4.getTime());
    }

    /**
     * A basic check for the testPreviousStandardDate() method when the
     * tick unit is 7 days (just for the sake of having a multiple).
     */
    @Test
    public void testPreviousStandardDateDayB() {
        MyDateAxis axis = new MyDateAxis("Day");
        Day apr12007 = new Day(1, 4, 2007);
        Day apr22007 = new Day(2, 4, 2007);

        // five dates to check...
        Date d0 = new Date(apr12007.getFirstMillisecond());
        Date d1 = new Date(apr12007.getFirstMillisecond() + 500L);
        Date d2 = new Date(apr12007.getMiddleMillisecond());
        Date d3 = new Date(apr12007.getMiddleMillisecond() + 500L);
        Date d4 = new Date(apr12007.getLastMillisecond());

        Date end = new Date(apr22007.getLastMillisecond());

        DateTickUnit unit = new DateTickUnit(DateTickUnitType.DAY, 7);
        axis.setTickUnit(unit);

        // START: check d0 and d1
        axis.setTickMarkPosition(DateTickMarkPosition.START);

        axis.setRange(d0, end);
        Date psd = axis.previousStandardDate(d0, unit);
        Date nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d0.getTime());
        assertTrue(nsd.getTime() >= d0.getTime());

        axis.setRange(d1, end);
        psd = axis.previousStandardDate(d1, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d1.getTime());
        assertTrue(nsd.getTime() >= d1.getTime());

        // MIDDLE: check d1, d2 and d3
        axis.setTickMarkPosition(DateTickMarkPosition.MIDDLE);

        axis.setRange(d1, end);
        psd = axis.previousStandardDate(d1, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d1.getTime());
        assertTrue(nsd.getTime() >= d1.getTime());

        axis.setRange(d2, end);
        psd = axis.previousStandardDate(d2, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d2.getTime());
        assertTrue(nsd.getTime() >= d2.getTime());

        axis.setRange(d3, end);
        psd = axis.previousStandardDate(d3, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d3.getTime());
        assertTrue(nsd.getTime() >= d3.getTime());

        // END: check d3 and d4
        axis.setTickMarkPosition(DateTickMarkPosition.END);

        axis.setRange(d3, end);
        psd = axis.previousStandardDate(d3, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d3.getTime());
        assertTrue(nsd.getTime() >= d3.getTime());

        axis.setRange(d4, end);
        psd = axis.previousStandardDate(d4, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d4.getTime());
        assertTrue(nsd.getTime() >= d4.getTime());
    }

    /**
     * A basic check for the testPreviousStandardDate() method when the
     * tick unit is 1 hour.
     */
    @Test
    public void testPreviousStandardDateHourA() {
        MyDateAxis axis = new MyDateAxis("Hour");
        Hour h0 = new Hour(12, 1, 4, 2007);
        Hour h1 = new Hour(13, 1, 4, 2007);

        // five dates to check...
        Date d0 = new Date(h0.getFirstMillisecond());
        Date d1 = new Date(h0.getFirstMillisecond() + 500L);
        Date d2 = new Date(h0.getMiddleMillisecond());
        Date d3 = new Date(h0.getMiddleMillisecond() + 500L);
        Date d4 = new Date(h0.getLastMillisecond());

        Date end = new Date(h1.getLastMillisecond());

        DateTickUnit unit = new DateTickUnit(DateTickUnitType.HOUR, 1);
        axis.setTickUnit(unit);

        // START: check d0 and d1
        axis.setTickMarkPosition(DateTickMarkPosition.START);

        axis.setRange(d0, end);
        Date psd = axis.previousStandardDate(d0, unit);
        Date nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d0.getTime());
        assertTrue(nsd.getTime() >= d0.getTime());

        axis.setRange(d1, end);
        psd = axis.previousStandardDate(d1, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d1.getTime());
        assertTrue(nsd.getTime() >= d1.getTime());

        // MIDDLE: check d1, d2 and d3
        axis.setTickMarkPosition(DateTickMarkPosition.MIDDLE);

        axis.setRange(d1, end);
        psd = axis.previousStandardDate(d1, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d1.getTime());
        assertTrue(nsd.getTime() >= d1.getTime());

        axis.setRange(d2, end);
        psd = axis.previousStandardDate(d2, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d2.getTime());
        assertTrue(nsd.getTime() >= d2.getTime());

        axis.setRange(d3, end);
        psd = axis.previousStandardDate(d3, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d3.getTime());
        assertTrue(nsd.getTime() >= d3.getTime());

        // END: check d3 and d4
        axis.setTickMarkPosition(DateTickMarkPosition.END);

        axis.setRange(d3, end);
        psd = axis.previousStandardDate(d3, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d3.getTime());
        assertTrue(nsd.getTime() >= d3.getTime());

        axis.setRange(d4, end);
        psd = axis.previousStandardDate(d4, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d4.getTime());
        assertTrue(nsd.getTime() >= d4.getTime());
    }

    /**
     * A basic check for the testPreviousStandardDate() method when the
     * tick unit is 6 hours (just for the sake of having a multiple).
     */
    @Test
    public void testPreviousStandardDateHourB() {
        MyDateAxis axis = new MyDateAxis("Hour");
        Hour h0 = new Hour(12, 1, 4, 2007);
        Hour h1 = new Hour(13, 1, 4, 2007);

        // five dates to check...
        Date d0 = new Date(h0.getFirstMillisecond());
        Date d1 = new Date(h0.getFirstMillisecond() + 500L);
        Date d2 = new Date(h0.getMiddleMillisecond());
        Date d3 = new Date(h0.getMiddleMillisecond() + 500L);
        Date d4 = new Date(h0.getLastMillisecond());

        Date end = new Date(h1.getLastMillisecond());

        DateTickUnit unit = new DateTickUnit(DateTickUnitType.HOUR, 6);
        axis.setTickUnit(unit);

        // START: check d0 and d1
        axis.setTickMarkPosition(DateTickMarkPosition.START);

        axis.setRange(d0, end);
        Date psd = axis.previousStandardDate(d0, unit);
        Date nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d0.getTime());
        assertTrue(nsd.getTime() >= d0.getTime());

        axis.setRange(d1, end);
        psd = axis.previousStandardDate(d1, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d1.getTime());
        assertTrue(nsd.getTime() >= d1.getTime());

        // MIDDLE: check d1, d2 and d3
        axis.setTickMarkPosition(DateTickMarkPosition.MIDDLE);

        axis.setRange(d1, end);
        psd = axis.previousStandardDate(d1, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d1.getTime());
        assertTrue(nsd.getTime() >= d1.getTime());

        axis.setRange(d2, end);
        psd = axis.previousStandardDate(d2, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d2.getTime());
        assertTrue(nsd.getTime() >= d2.getTime());

        axis.setRange(d3, end);
        psd = axis.previousStandardDate(d3, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d3.getTime());
        assertTrue(nsd.getTime() >= d3.getTime());

        // END: check d3 and d4
        axis.setTickMarkPosition(DateTickMarkPosition.END);

        axis.setRange(d3, end);
        psd = axis.previousStandardDate(d3, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d3.getTime());
        assertTrue(nsd.getTime() >= d3.getTime());

        axis.setRange(d4, end);
        psd = axis.previousStandardDate(d4, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d4.getTime());
        assertTrue(nsd.getTime() >= d4.getTime());
    }

    /**
     * A basic check for the testPreviousStandardDate() method when the
     * tick unit is 1 second.
     */
    @Test
    public void testPreviousStandardDateSecondA() {
        MyDateAxis axis = new MyDateAxis("Second");
        Second s0 = new Second(58, 31, 12, 1, 4, 2007);
        Second s1 = new Second(59, 31, 12, 1, 4, 2007);

        // five dates to check...
        Date d0 = new Date(s0.getFirstMillisecond());
        Date d1 = new Date(s0.getFirstMillisecond() + 50L);
        Date d2 = new Date(s0.getMiddleMillisecond());
        Date d3 = new Date(s0.getMiddleMillisecond() + 50L);
        Date d4 = new Date(s0.getLastMillisecond());

        Date end = new Date(s1.getLastMillisecond());

        DateTickUnit unit = new DateTickUnit(DateTickUnitType.SECOND, 1);
        axis.setTickUnit(unit);

        // START: check d0 and d1
        axis.setTickMarkPosition(DateTickMarkPosition.START);

        axis.setRange(d0, end);
        Date psd = axis.previousStandardDate(d0, unit);
        Date nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d0.getTime());
        assertTrue(nsd.getTime() >= d0.getTime());

        axis.setRange(d1, end);
        psd = axis.previousStandardDate(d1, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d1.getTime());
        assertTrue(nsd.getTime() >= d1.getTime());

        // MIDDLE: check d1, d2 and d3
        axis.setTickMarkPosition(DateTickMarkPosition.MIDDLE);

        axis.setRange(d1, end);
        psd = axis.previousStandardDate(d1, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d1.getTime());
        assertTrue(nsd.getTime() >= d1.getTime());

        axis.setRange(d2, end);
        psd = axis.previousStandardDate(d2, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d2.getTime());
        assertTrue(nsd.getTime() >= d2.getTime());

        axis.setRange(d3, end);
        psd = axis.previousStandardDate(d3, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d3.getTime());
        assertTrue(nsd.getTime() >= d3.getTime());

        // END: check d3 and d4
        axis.setTickMarkPosition(DateTickMarkPosition.END);

        axis.setRange(d3, end);
        psd = axis.previousStandardDate(d3, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d3.getTime());
        assertTrue(nsd.getTime() >= d3.getTime());

        axis.setRange(d4, end);
        psd = axis.previousStandardDate(d4, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d4.getTime());
        assertTrue(nsd.getTime() >= d4.getTime());
    }

    /**
     * A basic check for the testPreviousStandardDate() method when the
     * tick unit is 5 seconds (just for the sake of having a multiple).
     */
    @Test
    public void testPreviousStandardDateSecondB() {
        MyDateAxis axis = new MyDateAxis("Second");
        Second s0 = new Second(58, 31, 12, 1, 4, 2007);
        Second s1 = new Second(59, 31, 12, 1, 4, 2007);

        // five dates to check...
        Date d0 = new Date(s0.getFirstMillisecond());
        Date d1 = new Date(s0.getFirstMillisecond() + 50L);
        Date d2 = new Date(s0.getMiddleMillisecond());
        Date d3 = new Date(s0.getMiddleMillisecond() + 50L);
        Date d4 = new Date(s0.getLastMillisecond());

        Date end = new Date(s1.getLastMillisecond());

        DateTickUnit unit = new DateTickUnit(DateTickUnitType.SECOND, 5);
        axis.setTickUnit(unit);

        // START: check d0 and d1
        axis.setTickMarkPosition(DateTickMarkPosition.START);

        axis.setRange(d0, end);
        Date psd = axis.previousStandardDate(d0, unit);
        Date nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d0.getTime());
        assertTrue(nsd.getTime() >= d0.getTime());

        axis.setRange(d1, end);
        psd = axis.previousStandardDate(d1, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d1.getTime());
        assertTrue(nsd.getTime() >= d1.getTime());

        // MIDDLE: check d1, d2 and d3
        axis.setTickMarkPosition(DateTickMarkPosition.MIDDLE);

        axis.setRange(d1, end);
        psd = axis.previousStandardDate(d1, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d1.getTime());
        assertTrue(nsd.getTime() >= d1.getTime());

        axis.setRange(d2, end);
        psd = axis.previousStandardDate(d2, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d2.getTime());
        assertTrue(nsd.getTime() >= d2.getTime());

        axis.setRange(d3, end);
        psd = axis.previousStandardDate(d3, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d3.getTime());
        assertTrue(nsd.getTime() >= d3.getTime());

        // END: check d3 and d4
        axis.setTickMarkPosition(DateTickMarkPosition.END);

        axis.setRange(d3, end);
        psd = axis.previousStandardDate(d3, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d3.getTime());
        assertTrue(nsd.getTime() >= d3.getTime());

        axis.setRange(d4, end);
        psd = axis.previousStandardDate(d4, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d4.getTime());
        assertTrue(nsd.getTime() >= d4.getTime());
    }

    /**
     * A basic check for the testPreviousStandardDate() method when the
     * tick unit is 1 millisecond.
     */
    @Test
    public void testPreviousStandardDateMillisecondA() {
        MyDateAxis axis = new MyDateAxis("Millisecond");
        Millisecond m0 = new Millisecond(458, 58, 31, 12, 1, 4, 2007);
        Millisecond m1 = new Millisecond(459, 58, 31, 12, 1, 4, 2007);

        Date d0 = new Date(m0.getFirstMillisecond());
        Date end = new Date(m1.getLastMillisecond());

        DateTickUnit unit = new DateTickUnit(DateTickUnitType.MILLISECOND, 1);
        axis.setTickUnit(unit);

        // START: check d0
        axis.setTickMarkPosition(DateTickMarkPosition.START);

        axis.setRange(d0, end);
        Date psd = axis.previousStandardDate(d0, unit);
        Date nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d0.getTime());
        assertTrue(nsd.getTime() >= d0.getTime());

        // MIDDLE: check d0
        axis.setTickMarkPosition(DateTickMarkPosition.MIDDLE);

        axis.setRange(d0, end);
        psd = axis.previousStandardDate(d0, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d0.getTime());
        assertTrue(nsd.getTime() >= d0.getTime());

        // END: check d0
        axis.setTickMarkPosition(DateTickMarkPosition.END);

        axis.setRange(d0, end);
        psd = axis.previousStandardDate(d0, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d0.getTime());
        assertTrue(nsd.getTime() >= d0.getTime());
    }

    /**
     * A basic check for the testPreviousStandardDate() method when the
     * tick unit is 10 milliseconds (just for the sake of having a multiple).
     */
    @Test
    public void testPreviousStandardDateMillisecondB() {
        MyDateAxis axis = new MyDateAxis("Millisecond");
        Millisecond m0 = new Millisecond(458, 58, 31, 12, 1, 4, 2007);
        Millisecond m1 = new Millisecond(459, 58, 31, 12, 1, 4, 2007);

        Date d0 = new Date(m0.getFirstMillisecond());
        Date end = new Date(m1.getLastMillisecond());

        DateTickUnit unit = new DateTickUnit(DateTickUnitType.MILLISECOND, 10);
        axis.setTickUnit(unit);

        // START: check d0
        axis.setTickMarkPosition(DateTickMarkPosition.START);

        axis.setRange(d0, end);
        Date psd = axis.previousStandardDate(d0, unit);
        Date nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d0.getTime());
        assertTrue(nsd.getTime() >= d0.getTime());

        // MIDDLE: check d0
        axis.setTickMarkPosition(DateTickMarkPosition.MIDDLE);

        axis.setRange(d0, end);
        psd = axis.previousStandardDate(d0, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d0.getTime());
        assertTrue(nsd.getTime() >= d0.getTime());

        // END: check d0
        axis.setTickMarkPosition(DateTickMarkPosition.END);

        axis.setRange(d0, end);
        psd = axis.previousStandardDate(d0, unit);
        nsd = unit.addToDate(psd, TimeZone.getDefault());
        assertTrue(psd.getTime() < d0.getTime());
        assertTrue(nsd.getTime() >= d0.getTime());
    }

    /**
     * A test to reproduce bug 2201869.
     */
    @Test
    public void testBug2201869() {
        TimeZone tz = TimeZone.getTimeZone("GMT");
        GregorianCalendar c = new GregorianCalendar(tz, Locale.UK);
        DateAxis axis = new DateAxis("Date", tz, Locale.UK);
        SimpleDateFormat sdf = new SimpleDateFormat("d-MMM-yyyy", Locale.UK);
        sdf.setCalendar(c);
        axis.setTickUnit(new DateTickUnit(DateTickUnitType.MONTH, 1, sdf));
        Day d1 = new Day(1, 3, 2008);
        d1.peg(c);
        Day d2 = new Day(30, 6, 2008);
        d2.peg(c);
        axis.setRange(d1.getStart(), d2.getEnd());
        BufferedImage image = new BufferedImage(200, 100,
                BufferedImage.TYPE_INT_ARGB);
        Graphics2D g2 = image.createGraphics();
        Rectangle2D area = new Rectangle2D.Double(0.0, 0.0, 200, 100);
        axis.setTickMarkPosition(DateTickMarkPosition.END);
        List ticks = axis.refreshTicks(g2, new AxisState(), area,
                RectangleEdge.BOTTOM);
        assertEquals(3, ticks.size());
        DateTick t1 = (DateTick) ticks.get(0);
        assertEquals("31-Mar-2008", t1.getText());
        DateTick t2 = (DateTick) ticks.get(1);
        assertEquals("30-Apr-2008", t2.getText());
        DateTick t3 = (DateTick) ticks.get(2);
        assertEquals("31-May-2008", t3.getText());

        // now repeat for a vertical axis
        ticks = axis.refreshTicks(g2, new AxisState(), area,
                RectangleEdge.LEFT);
        assertEquals(3, ticks.size());
        t1 = (DateTick) ticks.get(0);
        assertEquals("31-Mar-2008", t1.getText());
        t2 = (DateTick) ticks.get(1);
        assertEquals("30-Apr-2008", t2.getText());
        t3 = (DateTick) ticks.get(2);
        assertEquals("31-May-2008", t3.getText());
    }

    @Test
    public void testBug3484403() {

        final long[] dates =
            { 1304892000000L, 1304632800000L, 1304546400000L, 1304460000000L,
              1304373600000L, 1304287200000L, 1320015600000L, 1309384800000L,
              1319752800000L, 1319666400000L, 1319580000000L, 1319493600000L };
        Arrays.sort(dates);

        DateAxis axis = new DateAxis("Date");
        // set start and end date
        Date start = new Date(dates[0]);
        Date end = new Date(dates[dates.length-1]);
        axis.setMinimumDate(start);
        axis.setMaximumDate(end);

        BufferedImage image = new BufferedImage(200, 100,
                BufferedImage.TYPE_INT_ARGB);
        Graphics2D g2 = image.createGraphics();
        Rectangle2D area = new Rectangle2D.Double(0.0, 0.0, 500, 200);

        // if the bug is still present, this leads to an endless loop
        axis.refreshTicks(g2, new AxisState(), area, RectangleEdge.BOTTOM);
    }
    
    /**
     * Test for bug #25 at Github.
     * 
     * https://github.com/jfree/jfreechart/issues/25
     * 
     */
    @Test
    public void testBug25() {
        TimeZone tz = TimeZone.getTimeZone("GMT");
        GregorianCalendar cal = new GregorianCalendar(tz, Locale.UK);
        
        MyDateAxis axis = new MyDateAxis("25");
        axis.setTimeZone(tz);
        
        // YEAR
        DateTickUnit ydtu = new DateTickUnit(DateTickUnitType.YEAR, 5);
        Year y = new Year(2015);
        long ymillis = y.getFirstMillisecond(cal); // 1420070400000L
        Date yprev = axis.previousStandardDate(new Date(ymillis), ydtu);
        assertEquals(new Year(2010).getFirstMillisecond(cal), yprev.getTime());
        
        // MONTH 
        DateTickUnit mdtu = new DateTickUnit(DateTickUnitType.MONTH, 3);
        Month m = new Month(12, 2016);
        long mmillis = m.getFirstMillisecond(cal); 
        Date mprev = axis.previousStandardDate(new Date(mmillis), mdtu);
        assertEquals(new Month(9, 2016).getFirstMillisecond(cal), 
                mprev.getTime());
        
        // DAY
        DateTickUnit ddtu = new DateTickUnit(DateTickUnitType.DAY, 7);
        Day d = new Day(14, 1, 2016);
        long dmillis = d.getFirstMillisecond(cal); 
        Date dprev = axis.previousStandardDate(new Date(dmillis), ddtu);
        assertEquals(new Day(7, 1, 2016).getFirstMillisecond(cal), 
                dprev.getTime());
        
        // HOUR
        DateTickUnit hdtu = new DateTickUnit(DateTickUnitType.HOUR, 6);
        Hour h = new Hour(18, 24, 8, 2016);
        long hmillis = h.getFirstMillisecond(cal); 
        Date hprev = axis.previousStandardDate(new Date(hmillis), hdtu);
        assertEquals(new Hour(12, 24, 8, 2016).getFirstMillisecond(cal), 
                hprev.getTime());
        
        // MINUTE
        DateTickUnit mindtu = new DateTickUnit(DateTickUnitType.MINUTE, 5);
        Minute min = new Minute(10, 12, 24, 8, 2016);
        long minmillis = min.getFirstMillisecond(cal); // 1472040600000L GMT
        Date minprev = axis.previousStandardDate(new Date(minmillis), mindtu);
        assertEquals(1472040600000L - 5 * 60 * 1000L, minprev.getTime());
        
        // SECOND 
        DateTickUnit sdtu = new DateTickUnit(DateTickUnitType.SECOND, 10);
        Second s = new Second(50, 30, 18, 24, 8, 2016);
        long smillis = s.getFirstMillisecond(cal); 
        Date sprev = axis.previousStandardDate(new Date(smillis), sdtu);
        assertEquals(new Second(40, 30, 18, 24, 8, 2016)
                .getFirstMillisecond(cal), sprev.getTime());
        
        // MILLISECOND
        DateTickUnit msdtu = new DateTickUnit(DateTickUnitType.MILLISECOND, 10);
        Millisecond ms = new Millisecond(500, 50, 30, 18, 24, 8, 2016);
        long msmillis = ms.getFirstMillisecond(cal); 
        Date msprev = axis.previousStandardDate(new Date(msmillis), msdtu);
        assertEquals(new Millisecond(490, 50, 30, 18, 24, 8, 2016)
                .getFirstMillisecond(cal), msprev.getTime());
        
    }
    
}
