/*
    * 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
    *
    *      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.apache.commons.rng.sampling;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.List;
  import org.apache.commons.rng.UniformRandomProvider;
  import org.junit.jupiter.api.Assertions;
  import org.junit.jupiter.api.Test;
  
  /**
   * Tests for {@link CollectionSampler}.
   */
  class CollectionSamplerTest {
  
      @Test
      void testSampleTrivial() {
          final ArrayList<String> list = new ArrayList<>();
          list.add("Apache");
          list.add("Commons");
          list.add("RNG");
  
          final CollectionSampler<String> sampler =
              new CollectionSampler<>(RandomAssert.createRNG(), list);
          final String word = sampler.sample();
          for (final String w : list) {
              if (word.equals(w)) {
                  return;
              }
          }
          Assertions.fail(word + " not in list");
      }
  
      @Test
      void testSamplePrecondition() {
          final UniformRandomProvider rng = RandomAssert.seededRNG();
          // Must fail for empty collection.
          final List<String> empty = Collections.emptyList();
          Assertions.assertThrows(IllegalArgumentException.class,
              () -> new CollectionSampler<>(rng, empty));
      }
  
      /**
       * Test the SharedStateSampler implementation.
       */
      @Test
      void testSharedStateSampler() {
          final UniformRandomProvider rng1 = RandomAssert.seededRNG();
          final UniformRandomProvider rng2 = RandomAssert.seededRNG();
          final List<String> list = Arrays.asList("Apache", "Commons", "RNG");
          final CollectionSampler<String> sampler1 =
              new CollectionSampler<>(rng1, list);
          final CollectionSampler<String> sampler2 = sampler1.withUniformRandomProvider(rng2);
          RandomAssert.assertProduceSameSequence(sampler1, sampler2);
      }
  }