/*
    * 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.apache.commons.statistics.distribution;
  
  import java.util.stream.Stream;
  import org.junit.jupiter.params.ParameterizedTest;
  import org.junit.jupiter.params.provider.Arguments;
  import org.junit.jupiter.params.provider.MethodSource;
  
  /**
   * Test for {@link Constants}.
   */
  class ConstantsTest {
      @ParameterizedTest
      @MethodSource
      void testConstant(double expected, double x, int ulp) {
          TestUtils.assertEquals(expected, x, DoubleTolerances.ulps(ulp));
      }
  
      static Stream<Arguments> testConstant() {
          final Stream.Builder<Arguments> builder = Stream.builder();
          builder.add(Arguments.of(Math.sqrt(2), Constants.ROOT_TWO, 0));
          builder.add(Arguments.of(Math.sqrt(2 / Math.PI), Constants.ROOT_TWO_DIV_PI, 0));
          builder.add(Arguments.of(Math.sqrt(Math.PI / 2), Constants.ROOT_PI_DIV_TWO, 1));
          builder.add(Arguments.of(Math.log(2), Constants.LN_TWO, 0));
          builder.add(Arguments.of(0.5 * Math.log(2 * Math.PI), Constants.HALF_LOG_TWO_PI, 1));
          return builder.build();
      }
  }