/*
    * 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.assertNull;
  import static org.junit.Assert.fail;
  
  import org.eclipse.jgit.revwalk.filter.RevFilter;
  import org.eclipse.jgit.treewalk.filter.TreeFilter;
  import org.junit.Test;
  
  public class RevWalkMergeBaseTest extends RevWalkTestCase {
  	@Test
  	public void testNone() throws Exception {
  		final RevCommit c1 = commit(commit(commit()));
  		final RevCommit c2 = commit(commit(commit()));
  
  		rw.setRevFilter(RevFilter.MERGE_BASE);
  		markStart(c1);
  		markStart(c2);
  		assertNull(rw.next());
  	}
  
  	@Test
  	public void testDisallowTreeFilter() throws Exception {
  		final RevCommit c1 = commit();
  		final RevCommit c2 = commit();
  
  		rw.setRevFilter(RevFilter.MERGE_BASE);
  		rw.setTreeFilter(TreeFilter.ANY_DIFF);
  		markStart(c1);
  		markStart(c2);
  		try {
  			assertNull(rw.next());
  			fail("did not throw IllegalStateException");
  		} catch (IllegalStateException ise) {
  			// expected result
  		}
  	}
  
  	@Test
  	public void testSimple() throws Exception {
  		final RevCommit a = commit();
  		final RevCommit b = commit(a);
  		final RevCommit c1 = commit(commit(commit(commit(commit(b)))));
  		final RevCommit c2 = commit(commit(commit(commit(commit(b)))));
  
  		rw.setRevFilter(RevFilter.MERGE_BASE);
  		markStart(c1);
  		markStart(c2);
  		assertCommit(b, rw.next());
  		assertNull(rw.next());
  	}
  
  	@Test
  	public void testMultipleHeads_SameBase1() throws Exception {
  		final RevCommit a = commit();
  		final RevCommit b = commit(a);
  		final RevCommit c1 = commit(commit(commit(commit(commit(b)))));
  		final RevCommit c2 = commit(commit(commit(commit(commit(b)))));
  		final RevCommit c3 = commit(commit(commit(b)));
  
  		rw.setRevFilter(RevFilter.MERGE_BASE);
  		markStart(c1);
  		markStart(c2);
  		markStart(c3);
  		assertCommit(b, rw.next());
  		assertNull(rw.next());
  	}
  
  	@Test
  	public void testMultipleHeads_SameBase2() throws Exception {
  		final RevCommit a = commit();
  		final RevCommit b = commit(a);
  		final RevCommit c = commit(b);
  		final RevCommit d1 = commit(commit(commit(commit(commit(b)))));
  		final RevCommit d2 = commit(commit(commit(commit(commit(c)))));
  		final RevCommit d3 = commit(commit(commit(c)));
  
  		rw.setRevFilter(RevFilter.MERGE_BASE);
  		markStart(d1);
  		markStart(d2);
  		markStart(d3);
  		assertCommit(b, rw.next());
  		assertNull(rw.next());
  	}
  
  	@Test
  	public void testCrissCross() throws Exception {
  		// See http://marc.info/?l=git&m=111463358500362&w=2 for a nice
  		// description of what this test is creating. We don't have a
 		// clean merge base for d,e as they each merged the parents b,c
 		// in different orders.
 		//
 		final RevCommit a = commit();
 		final RevCommit b = commit(a);
 		final RevCommit c = commit(a);
 		final RevCommit d = commit(b, c);
 		final RevCommit e = commit(c, b);
 
 		rw.setRevFilter(RevFilter.MERGE_BASE);
 		markStart(d);
 		markStart(e);
 		assertCommit(c, rw.next());
 		assertCommit(b, rw.next());
 		assertNull(rw.next());
 	}
 
 	@Test
 	public void testInconsistentCommitTimes() throws Exception {
 		// When commit times are inconsistent (a parent is younger than a child)
 		// make sure that not both, parent and child, are reported as merge
 		// base. In the following repo the merge base between C,D should be B.
 		// But when A is younger than B the MergeBaseGenerator used to generate
 		// A before it detected that B is also a merge base.
 		//
 		//   +---C
 		//  /   /
 		// A---B---D
 
 		final RevCommit a = commit(2);
 		final RevCommit b = commit(-1, a);
 		final RevCommit c = commit(2, b, a);
 		final RevCommit d = commit(1, b);
 
 		rw.setRevFilter(RevFilter.MERGE_BASE);
 		markStart(d);
 		markStart(c);
 		assertCommit(b, rw.next());
 		assertNull(rw.next());
 	}
 
 }