/*
    * Copyright (C) 2009, Google Inc. and others
    *
    * This program and the accompanying materials are made available under the
    * terms of the Eclipse Distribution License v. 1.0 which is available at
    * https://www.eclipse.org/org/documents/edl-v10.php.
    *
    * SPDX-License-Identifier: BSD-3-Clause
    */
  
  package org.eclipse.jgit.revwalk;
  
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertFalse;
  import static org.junit.Assert.assertNull;
  import static org.junit.Assert.assertTrue;
  import static org.junit.Assert.fail;
  
  import org.junit.Test;
  
  public class AlwaysEmptyRevQueueTest extends RevWalkTestCase {
  	private final AbstractRevQueue q = AbstractRevQueue.EMPTY_QUEUE;
  
  	@Test
  	public void testEmpty() throws Exception {
  		assertNull(q.next());
  		assertTrue(q.everbodyHasFlag(RevWalk.UNINTERESTING));
  		assertFalse(q.anybodyHasFlag(RevWalk.UNINTERESTING));
  		assertEquals(0, q.outputType());
  	}
  
  	@Test
  	public void testClear() throws Exception {
  		q.clear();
  		testEmpty();
  	}
  
  	@Test
  	public void testAddFails() throws Exception {
  		try {
  			q.add(commit());
  			fail("Did not throw UnsupportedOperationException");
  		} catch (UnsupportedOperationException e) {
  			// expected result
  		}
  	}
  }