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3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * CS licenses this file to You under the Apache License, Version 2.0
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9    *   http://www.apache.org/licenses/LICENSE-2.0
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12   * distributed under the License is distributed on an "AS IS" BASIS,
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14   * See the License for the specific language governing permissions and
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16   */
17  package org.orekit.time;
18  
19  
20  import org.junit.Assert;
21  import org.junit.Before;
22  import org.junit.Test;
23  import org.orekit.Utils;
24  import org.orekit.frames.ITRFVersion;
25  import org.orekit.utils.Constants;
26  import org.orekit.utils.IERSConventions;
27  
28  
29  public class TTScaleTest {
30  
31      @Test
32      public void testConstant() {
33          TimeScale scale = TimeScalesFactory.getTT();
34          Assert.assertEquals("TT", scale.toString());
35          double reference = scale.offsetFromTAI(AbsoluteDate.J2000_EPOCH);
36          for (double dt = -10000; dt < 10000; dt += 123.456789) {
37              AbsoluteDate date = AbsoluteDate.J2000_EPOCH.shiftedBy(dt * Constants.JULIAN_DAY);
38              Assert.assertEquals(reference, scale.offsetFromTAI(date), 1.0e-15);
39          }
40      }
41  
42      @Test
43      public void testSymmetry() {
44          TimeScale scale = TimeScalesFactory.getTT();
45          for (double dt = -10000; dt < 10000; dt += 123.456789) {
46              AbsoluteDate date = AbsoluteDate.J2000_EPOCH.shiftedBy(dt * Constants.JULIAN_DAY);
47              double dt1 = scale.offsetFromTAI(date);
48              DateTimeComponents components = date.getComponents(scale);
49              double dt2 = scale.offsetToTAI(components.getDate(), components.getTime());
50              Assert.assertEquals( 0.0, dt1 + dt2, 1.0e-10);
51          }
52      }
53  
54      @Test
55      public void testAAS06134() {
56  
57          // this reference test has been extracted from the following paper:
58          // Implementation Issues Surrounding the New IAU Reference Systems for Astrodynamics
59          // David A. Vallado, John H. Seago, P. Kenneth Seidelmann
60          // http://www.centerforspace.com/downloads/files/pubs/AAS-06-134.pdf
61          // Note that the dUT1 here is -0.439962, whereas it is -0.4399619 in the book
62          Utils.setLoaders(IERSConventions.IERS_1996,
63                           Utils.buildEOPList(IERSConventions.IERS_1996, ITRFVersion.ITRF_2008, new double[][] {
64                               { 53098, -0.439962, 0.0015563, -0.140682, 0.333309, -0.052195, -0.003875, Double.NaN, Double.NaN },
65                               { 53099, -0.439962, 0.0015563, -0.140682, 0.333309, -0.052195, -0.003875, Double.NaN, Double.NaN },
66                               { 53100, -0.439962, 0.0015563, -0.140682, 0.333309, -0.052195, -0.003875, Double.NaN, Double.NaN },
67                               { 53101, -0.439962, 0.0015563, -0.140682, 0.333309, -0.052195, -0.003875, Double.NaN, Double.NaN },
68                               { 53102, -0.439962, 0.0015563, -0.140682, 0.333309, -0.052195, -0.003875, Double.NaN, Double.NaN },
69                               { 53103, -0.439962, 0.0015563, -0.140682, 0.333309, -0.052195, -0.003875, Double.NaN, Double.NaN },
70                               { 53104, -0.439962, 0.0015563, -0.140682, 0.333309, -0.052195, -0.003875, Double.NaN, Double.NaN },
71                               { 53105, -0.439962, 0.0015563, -0.140682, 0.333309, -0.052195, -0.003875, Double.NaN, Double.NaN }
72                           }));
73          AbsoluteDate date =
74                  new AbsoluteDate(2004, 4, 6, 7, 51, 28.386009, TimeScalesFactory.getUTC());
75          DateTimeComponents components = date.getComponents(TimeScalesFactory.getTT());
76          Assert.assertEquals(2004,        components.getDate().getYear());
77          Assert.assertEquals(   4,        components.getDate().getMonth());
78          Assert.assertEquals(   6,        components.getDate().getDay());
79          Assert.assertEquals(   7,        components.getTime().getHour());
80          Assert.assertEquals(  52,        components.getTime().getMinute());
81          Assert.assertEquals(  32.570009, components.getTime().getSecond(), 1.0e-10);
82  
83      }
84  
85      @Test
86      public void testDuringLeap() {
87          final TimeScale utc   = TimeScalesFactory.getUTC();
88          final TimeScale scale = TimeScalesFactory.getTT();
89          final AbsoluteDate before = new AbsoluteDate(new DateComponents(1983, 06, 30),
90                                                       new TimeComponents(23, 59, 59),
91                                                       utc);
92          final AbsoluteDate during = before.shiftedBy(1.25);
93          Assert.assertEquals(61, utc.minuteDuration(during));
94          Assert.assertEquals(1.0, utc.getLeap(during), 1.0e-10);
95          Assert.assertEquals(60, scale.minuteDuration(during));
96          Assert.assertEquals(0.0, scale.getLeap(during), 1.0e-10);
97      }
98  
99      @Before
100     public void setUp() {
101         Utils.setDataRoot("regular-data");
102     }
103 
104 }