/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF 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.
   */
  
  /*
   * This is not the original file distributed by the Apache Software Foundation
   * It has been modified by the Hipparchus project
   */
  package org.hipparchus.analysis.integration.gauss;
  
  import org.hipparchus.analysis.UnivariateFunction;
  import org.hipparchus.analysis.function.Constant;
  import org.hipparchus.util.Pair;
  import org.junit.jupiter.api.Test;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  
  /**
   * Test for {@link GaussIntegrator} class.
   *
   */
  class GaussIntegratorTest {
      @Test
      void testGetWeights() {
          final double[] points = { 0, 1.2, 3.4 };
          final double[] weights = { 9.8, 7.6, 5.4 };
  
          final GaussIntegrator integrator
              = new GaussIntegrator(new Pair<double[], double[]>(points, weights));
  
          assertEquals(weights.length, integrator.getNumberOfPoints());
  
          for (int i = 0; i < integrator.getNumberOfPoints(); i++) {
              assertEquals(weights[i], integrator.getWeight(i), 0d);
          }
      }
  
      @Test
      void testGetPoints() {
          final double[] points = { 0, 1.2, 3.4 };
          final double[] weights = { 9.8, 7.6, 5.4 };
  
          final GaussIntegrator integrator
              = new GaussIntegrator(new Pair<double[], double[]>(points, weights));
  
          assertEquals(points.length, integrator.getNumberOfPoints());
  
          for (int i = 0; i < integrator.getNumberOfPoints(); i++) {
              assertEquals(points[i], integrator.getPoint(i), 0d);
          }
      }
  
      @Test
      void testIntegrate() {
          final double[] points = { 0, 1, 2, 3, 4, 5 };
          final double[] weights = { 1, 1, 1, 1, 1, 1 };
  
          final GaussIntegrator integrator
              = new GaussIntegrator(new Pair<double[], double[]>(points, weights));
  
          final double val = 123.456;
          final UnivariateFunction c = new Constant(val);
  
          final double s = integrator.integrate(c);
          assertEquals(points.length * val, s, 0d);
      }
  }