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    * contributor license agreements.  See the NOTICE file distributed with
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    * CS licenses this file to You under the Apache License, Version 2.0
    * (the "License"); you may not use this file except in compliance with
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    *
    *   http://www.apache.org/licenses/LICENSE-2.0
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   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
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   * See the License for the specific language governing permissions and
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  package org.orekit.propagation.semianalytical.dsst.utilities;
  
  import org.junit.jupiter.api.Assertions;
  import org.junit.jupiter.api.BeforeEach;
  import org.junit.jupiter.api.Test;
  import org.orekit.Utils;
  
  public class NewcombOperatorTest {
  
      @Test
      public void recursionTest() {
  
          for (int n = 2; n < 10; n++) {
              final int mnm1 = -n - 1;
              for (int s = 0; s < 10; s++) {
                  final double newcomb10 = NewcombOperators.getValue(1, 0, mnm1, s);
                  final double newcalc10 = (s - mnm1 / 2.);
                  Assertions.assertEquals(newcalc10, newcomb10, 0.);
                  final double newcomb11 = NewcombOperators.getValue(1, 1, mnm1, s);
                  final double newcalc11 = (-8 * s * s + 2 * mnm1 * mnm1 + 10 * mnm1 + 12) / 8.;
                  Assertions.assertEquals(newcalc11, newcomb11, 0.);
                  final double newcomb20 = NewcombOperators.getValue(2, 0, mnm1, s);
                  final double newcalc20 = (4. * s * s + 5 * s - 4 * mnm1 * s + mnm1 * mnm1 - 3 * mnm1) / 8.;
                  Assertions.assertEquals(newcalc20, newcomb20, 0.);
                  final double newcomb02 = NewcombOperators.getValue(0, 2, mnm1, s);
                  final double newcalc02 = (4. * s * s - 5 * s + 4 * mnm1 * s + mnm1 * mnm1 - 3 * mnm1) / 8.;
                  Assertions.assertEquals(newcalc02, newcomb02, 0.);
                  final double newcomb21 = NewcombOperators.getValue(2, 1, mnm1, s);
                  final double newcalc21 = -s*s*s/2. + (mnm1*s*s)/4. - (5.*s*s)/8. + (mnm1*mnm1*s)/8. + (21.*mnm1*s)/16. + (11*s)/8. - mnm1*mnm1*mnm1/16. - (7.*mnm1*mnm1)/16. - (9.*mnm1)/16.;
                  Assertions.assertEquals(newcalc21, newcomb21, 1.e-14);
                  final double newcomb12 = NewcombOperators.getValue(1, 2, mnm1, s);
                  final double newcalc12 =  s*s*s/2. + (mnm1*s*s)/4. - (5.*s*s)/8. - (mnm1*mnm1*s)/8. - (21.*mnm1*s)/16. - (11*s)/8. - mnm1*mnm1*mnm1/16. - (7.*mnm1*mnm1)/16. - (9.*mnm1)/16.;
                  Assertions.assertEquals(newcalc12, newcomb12, 1.e-14);
                  final double newcomb22 = NewcombOperators.getValue(2, 2, mnm1, s);
                  final double newcalc22 = s*s*s*s/4. - (mnm1*mnm1*s*s)/8. - mnm1*s*s - (105.*s*s)/64. + mnm1*mnm1*mnm1*mnm1/64. + (7.*mnm1*mnm1*mnm1)/32. + (71.*mnm1*mnm1)/64. + (77.*mnm1)/32. + 15./8.;
                  Assertions.assertEquals(newcalc22, newcomb22, 1.e-14);
              }
          }
      }
  
      @Test
      public void valueRefTest() {
          final int n   = -17;
          final int s   = 14;
          final int rho = 12;
          final int sig = 12;
          final double value = NewcombOperators.getValue(rho, sig, n, s);
          Assertions.assertEquals(value, 90061805802.16286, 0.1);
      }
  
      @BeforeEach
      public void setUp() {
          Utils.clearFactories();
      }
  
  }