/*
    * 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
    *
    *      http://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.util;
  
  import org.hipparchus.CalculusFieldElement;
  import org.hipparchus.exception.MathIllegalStateException;
  import org.junit.jupiter.api.Test;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  
  /**
   * Tests for ContinuedFraction.
   */
  class FieldContinuedFractionTest {
  
      @Test
      void testGoldenRatio() {
          FieldContinuedFraction cf = new FieldContinuedFraction() {
  
              @Override
              public <T extends CalculusFieldElement<T>> T getA(final int n, final T x) {
                  return x.getField().getOne();
              }
  
              @Override
              public <T extends CalculusFieldElement<T>> T getB(final int n, final T x) {
                  return x.getField().getOne();
              }
  
          };
  
          Binary64 gr = cf.evaluate(new Binary64(0.0), 10e-9);
          assertEquals(1.61803399, gr.getReal(), 10e-9);
      }
  
      @Test
      void testNonConvergentContinuedFraction() {
          assertThrows(MathIllegalStateException.class, () -> {
              FieldContinuedFraction cf = new FieldContinuedFraction() {
  
                  @Override
                  public <T extends CalculusFieldElement<T>> T getA(final int n, final T x) {
                      return x.getField().getOne();
                  }
  
                  @Override
                  public <T extends CalculusFieldElement<T>> T getB(final int n, final T x) {
                      return x.getField().getOne();
                  }
  
              };
  
              cf.evaluate(new Binary64(0.0), 10e-9, 10);
          });
      }
  
      @Test
      void testInfinityDivergence() {
          assertThrows(MathIllegalStateException.class, () -> {
              FieldContinuedFraction cf = new FieldContinuedFraction() {
  
                  @Override
                  public <T extends CalculusFieldElement<T>> T getA(final int n, final T x) {
                      return x.getField().getOne().divide(n);
                  }
  
                  @Override
                  public <T extends CalculusFieldElement<T>> T getB(final int n, final T x) {
                      return x.getField().getOne();
                  }
  
              };
  
              cf.evaluate(new Binary64(1));
          });
      }
  }