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 com.datastax.oss.driver.internal.core.channel;
  
  import static com.datastax.oss.driver.Assertions.assertThat;
  
  import org.junit.Test;
  
  public class StreamIdGeneratorTest {
    @Test
    public void should_have_all_available_upon_creation() {
      StreamIdGenerator generator = new StreamIdGenerator(8);
      assertThat(generator.getAvailableIds()).isEqualTo(8);
    }
  
    @Test
    public void should_return_available_ids_in_sequence() {
      StreamIdGenerator generator = new StreamIdGenerator(8);
      for (int i = 0; i < 8; i++) {
        assertThat(generator.preAcquire()).isTrue();
        assertThat(generator.acquire()).isEqualTo(i);
        assertThat(generator.getAvailableIds()).isEqualTo(7 - i);
      }
    }
  
    @Test
    public void should_return_minus_one_when_no_id_available() {
      StreamIdGenerator generator = new StreamIdGenerator(8);
      for (int i = 0; i < 8; i++) {
        assertThat(generator.preAcquire()).isTrue();
        // also validating that ids are held as soon as preAcquire() is called, even if acquire() has
        // not been invoked yet
      }
      assertThat(generator.getAvailableIds()).isEqualTo(0);
      assertThat(generator.preAcquire()).isFalse();
    }
  
    @Test
    public void should_return_previously_released_ids() {
      StreamIdGenerator generator = new StreamIdGenerator(8);
      for (int i = 0; i < 8; i++) {
        assertThat(generator.preAcquire()).isTrue();
        assertThat(generator.acquire()).isEqualTo(i);
      }
      generator.release(7);
      generator.release(2);
      assertThat(generator.getAvailableIds()).isEqualTo(2);
      assertThat(generator.preAcquire()).isTrue();
      assertThat(generator.acquire()).isEqualTo(2);
      assertThat(generator.preAcquire()).isTrue();
      assertThat(generator.acquire()).isEqualTo(7);
      assertThat(generator.preAcquire()).isFalse();
    }
  }
  