/*
    * 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.collections4.bloomfilter;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  
  import org.junit.jupiter.params.ParameterizedTest;
  import org.junit.jupiter.params.provider.CsvSource;
  
  public abstract class AbstractHasherTest extends AbstractIndexProducerTest {
  
      protected abstract Hasher createEmptyHasher();
  
      @Override
      protected IndexProducer createEmptyProducer() {
          return createEmptyHasher().indices(getTestShape());
      }
  
      protected abstract Hasher createHasher();
  
      @Override
      protected IndexProducer createProducer() {
          return createHasher().indices(getTestShape());
      }
  
      /**
       * A method to get the number of items in a hasher. Mostly applies to
       * Collections of hashers.
       * @param hasher the hasher to check.
       * @return the number of hashers in the hasher
       */
      protected abstract int getHasherSize(Hasher hasher);
  
      /**
       * The shape of the Hashers filters for testing.
       * <ul>
       *  <li>Hash functions (k) = 17
       *  <li>Number of bits (m) = 72
       * </ul>
       * @return the testing shape.
       */
      protected final Shape getTestShape() {
          return Shape.fromKM(17, 72);
      }
  
      @ParameterizedTest
      @CsvSource({
          "17, 72",
          "3, 14",
          "5, 67868",
          "75, 10"
      })
      public void testHashing(final int k, final int m) {
          final int[] count = {0};
          final Hasher hasher = createHasher();
          hasher.indices(Shape.fromKM(k, m)).forEachIndex(i -> {
              assertTrue(i >= 0 && i < m, () -> "Out of range: " + i + ", m=" + m);
              count[0]++;
              return true;
          });
          assertEquals(k * getHasherSize(hasher), count[0],
                  () -> String.format("Did not produce k=%d * m=%d indices", k, getHasherSize(hasher)));
  
          // test early exit
          count[0] = 0;
          hasher.indices(Shape.fromKM(k, m)).forEachIndex(i -> {
              assertTrue(i >= 0 && i < m, () -> "Out of range: " + i + ", m=" + m);
              count[0]++;
              return false;
          });
          assertEquals(1, count[0], "did not exit early");
      }
  }