/*
    * Licensed to the Hipparchus project under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The Hipparchus project 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
    *
    *      https://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.hipparchus.distribution;
  
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertTrue;
  import static org.junit.Assert.fail;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import org.hipparchus.exception.MathIllegalArgumentException;
  import org.hipparchus.util.MathArrays;
  import org.hipparchus.util.Pair;
  import org.junit.Test;
  
  public class EnumeratedDistributionTest {
  
      @Test
      public void testCheckAndNormalizeBadArguments() {
          double[] bad = new double[] {-1, 0, 1, 1};
          try {
              EnumeratedDistribution.checkAndNormalize(bad);
              fail("Expecting IAE - negative probability");
          } catch (MathIllegalArgumentException ex) {
              // expected
          }
          bad = new double[] {0, Double.NaN, 1, 1};
          try {
              EnumeratedDistribution.checkAndNormalize(bad);
              fail("Expecting IAE - NaN probability");
          } catch (MathIllegalArgumentException ex) {
              // expected
          }
          bad = new double[] {0, Double.POSITIVE_INFINITY, 1, 1};
          try {
              EnumeratedDistribution.checkAndNormalize(bad);
              fail("Expecting IAE - infinite probability");
          } catch (MathIllegalArgumentException ex) {
              // expected
          }
          bad = new double[] {0, 0, 0, 0};
          try {
              EnumeratedDistribution.checkAndNormalize(bad);
              fail("Expecting IAE - no positive probabilities");
          } catch (MathIllegalArgumentException ex) {
              // expected
          }
          bad = new double[] {};
          try {
              EnumeratedDistribution.checkAndNormalize(bad);
              fail("Expecting IAE - empty probability array");
          } catch (MathIllegalArgumentException ex) {
              // expected
          }
          bad = null;
          try {
              EnumeratedDistribution.checkAndNormalize(bad);
              fail("Expecting IAE - empty probability array");
          } catch (MathIllegalArgumentException ex) {
              // expected
          }
      }
  
      @Test
      public void testCheckAndNormalize() {
          double[] p = new double[] {0, 2, 2, 1};
          double[] normP = EnumeratedDistribution.checkAndNormalize(p);
          assertEquals(0, normP[0], 0);
          assertEquals(0.4, normP[1], 0);
          assertEquals(0.4, normP[2], 0);
          assertEquals(0.2, normP[3], 0);
          p = new double[] {0.2, 0.2, 0.4, 0.2};
          assertTrue(MathArrays.equals(p, EnumeratedDistribution.checkAndNormalize(p)));
      }
  
      @Test
      public void testNullValues() {
          final List<Pair<String, Double>> pmf = new ArrayList<>();
          pmf.add(new Pair<>("a", 0.5));
          pmf.add(new Pair<>(null, 0.5));
          final EnumeratedDistribution<String> dist = new EnumeratedDistribution<>(pmf);
          assertEquals(0.5, dist.probability(null), 0);
          assertEquals(0.5, dist.probability("a"), 0);
          assertEquals(0, dist.probability("b"), 0);
     }
 
     @Test
     public void testRepeatedValues() {
         final List<Pair<String, Double>> pmf = new ArrayList<>();
         pmf.add(new Pair<>("a", 0.5));
         pmf.add(new Pair<>("a", 0.5));
         pmf.add(new Pair<>("b", 0.0));
         final EnumeratedDistribution<String> dist = new EnumeratedDistribution<>(pmf);
         assertEquals(0, dist.probability(null), 0);
         assertEquals(1, dist.probability("a"), 0);
         assertEquals(0, dist.probability("b"), 0);
         assertEquals(0, dist.probability("c"), 0);
     }
 }