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