/*
    * 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.
   */
  package org.hipparchus.analysis.differentiation;
  
  import org.hipparchus.Field;
  import org.hipparchus.exception.MathIllegalArgumentException;
  import org.hipparchus.exception.MathRuntimeException;
  import org.hipparchus.exception.NullArgumentException;
  import org.hipparchus.util.FastMath;
  import org.junit.jupiter.api.Test;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  
  class DerivativeTest {
  
      private static final double TOLERANCE = 1e-10;
  
      @Test
      void testGetReal() {
          // GIVEN
          final double expectedOperation = 0.5;
          final TestDerivative testDerivative = new TestDerivative(expectedOperation);
          // WHEN
          final double actualOperation = testDerivative.getReal();
          // THEN
          assertEquals(expectedOperation, actualOperation, 0.);
      }
  
      @Test
      void testAddDouble() {
          // GIVEN
          final double value = 0.5;
          final TestDerivative testDerivative = new TestDerivative(value);
          final double scalar = 2.;
          // WHEN
          final TestDerivative actualOperation = testDerivative.add(scalar);
          // THEN
          final TestDerivative expectedOperation = new TestDerivative(value + scalar);
          assertEquals(expectedOperation.getValue(), actualOperation.getValue(), TOLERANCE);
      }
  
      @Test
      void testSubtractDouble() {
          // GIVEN
          final double value = 0.5;
          final TestDerivative testDerivative = new TestDerivative(value);
          final double scalar = 2.;
          // WHEN
          final TestDerivative actualOperation = testDerivative.subtract(scalar);
          // THEN
          final TestDerivative expectedOperation = new TestDerivative(value - scalar);
          assertEquals(expectedOperation.getValue(), actualOperation.getValue(), TOLERANCE);
      }
  
      @Test
      void testLog10() {
          // GIVEN
          final double value = 0.5;
          final TestDerivative testDerivative = new TestDerivative(value);
          // WHEN
          final TestDerivative actualOperation = testDerivative.log10();
          // THEN
          final TestDerivative expectedOperation = new TestDerivative(FastMath.log10(value));
          assertEquals(expectedOperation.getValue(), actualOperation.getValue(), TOLERANCE);
      }
  
      @Test
      void testPow() {
          // GIVEN
          final double value1 = 2.;
          final double value2 = 3.;
          final TestDerivative testDerivative1 = new TestDerivative(value1);
          final TestDerivative testDerivative2 = new TestDerivative(value2);
          // WHEN
          final TestDerivative actualOperation = testDerivative1.pow(testDerivative2);
          // THEN
          final TestDerivative expectedOperation = new TestDerivative(FastMath.pow(value1, value2));
          assertEquals(expectedOperation.getValue(), actualOperation.getValue(), TOLERANCE);
      }
  
      @Test
      void testCosh() {
          // GIVEN
          final double value = 0.5;
          final TestDerivative testDerivative = new TestDerivative(value);
         // WHEN
         final TestDerivative actualOperation = testDerivative.cosh();
         // THEN
         final TestDerivative expectedOperation = new TestDerivative(FastMath.cosh(value));
         assertEquals(expectedOperation, actualOperation);
     }
 
     @Test
     void testSinh() {
         // GIVEN
         final double value = 0.5;
         final TestDerivative testDerivative = new TestDerivative(value);
         // WHEN
         final TestDerivative actualOperation = testDerivative.sinh();
         // THEN
         final TestDerivative expectedOperation = new TestDerivative(FastMath.sinh(value));
         assertEquals(expectedOperation, actualOperation);
     }
 
     @Test
     void testAcos() {
         // GIVEN
         final double value = 0.5;
         final TestDerivative testDerivative = new TestDerivative(value);
         // WHEN
         final TestDerivative actualOperation = testDerivative.acos();
         // THEN
         final TestDerivative expectedOperation = new TestDerivative(FastMath.acos(value));
         assertEquals(expectedOperation.getValue(), actualOperation.getValue(), TOLERANCE);
     }
 
     static class TestDerivative implements Derivative<TestDerivative> {
 
         private final double value;
 
         TestDerivative (final double value) {
             this.value = value;
         }
 
         @Override
         public TestDerivative getAddendum() {
             return subtract(getReal());
         }
 
         @Override
         public TestDerivative newInstance(double value) {
             return new TestDerivative(value);
         }
 
         @Override
         public TestDerivative scalb(int n) {
             return null;
         }
 
         @Override
         public TestDerivative hypot(TestDerivative y) throws MathIllegalArgumentException {
             return null;
         }
 
         @Override
         public TestDerivative exp() {
             return new TestDerivative(FastMath.exp(value));
         }
 
         @Override
         public TestDerivative expm1() {
             return null;
         }
 
         @Override
         public TestDerivative log() {
             return new TestDerivative(FastMath.log(value));
         }
 
         @Override
         public TestDerivative log1p() {
             return null;
         }
 
         @Override
         public TestDerivative cos() {
             return null;
         }
 
         @Override
         public TestDerivative sin() {
             return null;
         }
 
         @Override
         public TestDerivative asin() {
             return new TestDerivative(FastMath.asin(value));
         }
 
         @Override
         public TestDerivative atan() {
             return null;
         }
 
         @Override
         public TestDerivative atan2(TestDerivative x) throws MathIllegalArgumentException {
             return null;
         }
 
         @Override
         public TestDerivative acosh() {
             return null;
         }
 
         @Override
         public TestDerivative asinh() {
             return null;
         }
 
         @Override
         public TestDerivative atanh() {
             return null;
         }
 
         @Override
         public TestDerivative linearCombination(TestDerivative[] a, TestDerivative[] b) throws MathIllegalArgumentException {
             return null;
         }
 
         @Override
         public TestDerivative linearCombination(TestDerivative a1, TestDerivative b1, TestDerivative a2, TestDerivative b2) {
             return null;
         }
 
         @Override
         public TestDerivative linearCombination(TestDerivative a1, TestDerivative b1, TestDerivative a2, TestDerivative b2,
                                                 TestDerivative a3, TestDerivative b3) {
             return null;
         }
 
         @Override
         public TestDerivative linearCombination(TestDerivative a1, TestDerivative b1, TestDerivative a2, TestDerivative b2,
                                                 TestDerivative a3, TestDerivative b3, TestDerivative a4, TestDerivative b4) {
             return null;
         }
 
         @Override
         public TestDerivative remainder(TestDerivative a) {
             return null;
         }
 
         @Override
         public TestDerivative copySign(TestDerivative sign) {
             return null;
         }
 
         @Override
         public TestDerivative abs() {
             return null;
         }
 
         @Override
         public TestDerivative add(TestDerivative a) throws NullArgumentException {
             return new TestDerivative(value + a.value);
         }
 
         @Override
         public TestDerivative negate() {
             return new TestDerivative(-value);
         }
 
         @Override
         public TestDerivative multiply(TestDerivative a) throws NullArgumentException {
             return new TestDerivative(value * a.value);
         }
 
         @Override
         public TestDerivative reciprocal() throws MathRuntimeException {
             return new TestDerivative(1. / value);
         }
 
         @Override
         public Field<TestDerivative> getField() {
             return null;
         }
 
         @Override
         public int getFreeParameters() {
             return 0;
         }
 
         @Override
         public int getOrder() {
             return 0;
         }
 
         @Override
         public double getValue() {
             return value;
         }
 
         @Override
         public double getPartialDerivative(int... orders) throws MathIllegalArgumentException {
             return 0;
         }
 
         @Override
         public TestDerivative compose(double... f) throws MathIllegalArgumentException {
             return null;
         }
 
         @Override
         public boolean equals(Object obj) {
             if (obj instanceof DerivativeTest.TestDerivative) {
                 return Double.compare(value, ((DerivativeTest.TestDerivative) obj).value) == 0;
             } else {
                 return false;
             }
         }
     }
 
 }