code: /*
   * Copyright (c) 2019 the Eclipse Milo Authors
   *
   * This program and the accompanying materials are made
   * available under the terms of the Eclipse Public License 2.0
   * which is available at https://www.eclipse.org/legal/epl-2.0/
   *
   * SPDX-License-Identifier: EPL-2.0
   */
  
  package org.eclipse.milo.opcua.sdk.client.subscriptions;
  
  import org.eclipse.milo.opcua.sdk.client.subscriptions.OpcUaSubscription.ClientHandleSequence;
  import org.eclipse.milo.opcua.stack.core.types.builtin.unsigned.UInteger;
  import org.testng.annotations.Test;
  
  import static org.eclipse.milo.opcua.stack.core.types.builtin.unsigned.Unsigned.uint;
  import static org.testng.Assert.assertEquals;
  import static org.testng.Assert.assertThrows;
  
  public class ClientHandleSequenceTest {
  
      @Test
      public void testRollover() {
          ClientHandleSequence sequence = new ClientHandleSequence(h -> false, UInteger.MAX_VALUE - 1);
  
          assertEquals(uint(UInteger.MAX_VALUE - 1), sequence.nextClientHandle());
          assertEquals(UInteger.MAX, sequence.nextClientHandle());
          assertEquals(uint(0), sequence.nextClientHandle());
          assertEquals(uint(1), sequence.nextClientHandle());
      }
  
      @Test
      public void testInUsePredicate() {
          ClientHandleSequence sequence = new ClientHandleSequence(h -> h.longValue() < 10);
  
          assertEquals(uint(10), sequence.nextClientHandle());
      }
  
      // Slow; enable to test manually.
      @Test(enabled = false)
      public void testThrowsIfAllUsed() {
          ClientHandleSequence sequence = new ClientHandleSequence(h -> true);
  
          assertThrows(IllegalStateException.class, sequence::nextClientHandle);
      }
  
  }