content: /*
   * 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.kafka.streams.processor.internals;
  
  import org.junit.jupiter.api.Test;
  
  import java.util.HashSet;
  import java.util.Set;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertNotEquals;
  
  public class QuickUnionTest {
  
      @Test
      public void testUnite() {
          final QuickUnion<Long> qu = new QuickUnion<>();
  
          final long[] ids = {
              1L, 2L, 3L, 4L, 5L
          };
  
          for (final long id : ids) {
              qu.add(id);
          }
  
          assertEquals(5, roots(qu, ids).size());
  
          qu.unite(1L, 2L);
          assertEquals(4, roots(qu, ids).size());
          assertEquals(qu.root(1L), qu.root(2L));
  
          qu.unite(3L, 4L);
          assertEquals(3, roots(qu, ids).size());
          assertEquals(qu.root(1L), qu.root(2L));
          assertEquals(qu.root(3L), qu.root(4L));
  
          qu.unite(1L, 5L);
          assertEquals(2, roots(qu, ids).size());
          assertEquals(qu.root(1L), qu.root(2L));
          assertEquals(qu.root(2L), qu.root(5L));
          assertEquals(qu.root(3L), qu.root(4L));
  
          qu.unite(3L, 5L);
          assertEquals(1, roots(qu, ids).size());
          assertEquals(qu.root(1L), qu.root(2L));
          assertEquals(qu.root(2L), qu.root(3L));
          assertEquals(qu.root(3L), qu.root(4L));
          assertEquals(qu.root(4L), qu.root(5L));
      }
  
      @Test
      public void testUniteMany() {
          final QuickUnion<Long> qu = new QuickUnion<>();
  
          final long[] ids = {
              1L, 2L, 3L, 4L, 5L
          };
  
          for (final long id : ids) {
              qu.add(id);
          }
  
          assertEquals(5, roots(qu, ids).size());
  
          qu.unite(1L, 2L, 3L, 4L);
          assertEquals(2, roots(qu, ids).size());
          assertEquals(qu.root(1L), qu.root(2L));
          assertEquals(qu.root(2L), qu.root(3L));
          assertEquals(qu.root(3L), qu.root(4L));
          assertNotEquals(qu.root(1L), qu.root(5L));
      }
  
      private Set<Long> roots(final QuickUnion<Long> qu, final long... ids) {
          final HashSet<Long> roots = new HashSet<>();
          for (final long id : ids) {
              roots.add(qu.root(id));
          }
          return roots;
      }
  }
  