/*
* Copyright 2008 Network Engine for Objects in Lund AB [neotechnology.com]
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.neo4j.graphalgo.shortestPath;
import org.neo4j.graphalgo.shortestpath.FindSingleShortestPath;
import org.neo4j.graphalgo.testUtil.Neo4jAlgoTestCase;
import org.neo4j.graphalgo.testUtil.SimpleGraphBuilder;
import org.neo4j.graphdb.Node;
public class FindSingleShortestPathTest extends Neo4jAlgoTestCase
{
public FindSingleShortestPathTest( String arg0 )
{
super( arg0 );
}
protected FindSingleShortestPath getFindPath( SimpleGraphBuilder graph,
String startNode, String endNode, int maxDepth )
{
return new FindSingleShortestPath( graph.getNode( startNode ), graph
.getNode( endNode ), MyRelTypes.R1, maxDepth );
}
/**
* Test case for just a single node (path length zero)
*/
public void testFindPathMinimal()
{
graph.makeNode( "lonely" );
FindSingleShortestPath findPath = getFindPath( graph, "lonely", "lonely",
Integer.MAX_VALUE );
assertTrue( findPath.getPathAsNodes().size() == 1 );
}
/**
* Test case for a path of length zero, with some surrounding nodes
*/
public void testFindPathMinimal2()
{
graph.makeEdge( "a", "b", "cost", (double) 1 );
graph.makeEdge( "a", "c", "cost", (double) 1 );
graph.makeEdge( "a", "d", "cost", (double) 1 );
graph.makeEdge( "a", "e", "cost", (double) 1 );
graph.makeEdge( "b", "c", "cost", (double) 1 );
graph.makeEdge( "c", "d", "cost", (double) 1 );
graph.makeEdge( "d", "e", "cost", (double) 1 );
graph.makeEdge( "e", "f", "cost", (double) 1 );
FindSingleShortestPath findPath = getFindPath( graph, "a", "a",
Integer.MAX_VALUE );
assertTrue( findPath.getPathAsNodes().size() == 1 );
assertTrue( findPath.getPathAsRelationships().size() == 0 );
assertTrue( findPath.getPath().size() == 1 );
}
public void testFindPathDepthLimit()
{
graph.makeEdgeChain( "a,b,c,d" );
FindSingleShortestPath findPath = getFindPath( graph, "a", "d", 3 );
assertTrue( findPath.getPathAsNodes() != null );
assertTrue( findPath.getPathAsNodes().size() == 4 );
findPath = getFindPath( graph, "a", "d", 2 );
assertTrue( findPath.getPathAsNodes() == null );
findPath = getFindPath( graph, "a", "c", 2 );
assertTrue( findPath.getPathAsNodes() != null );
findPath = getFindPath( graph, "a", "c", 1 );
assertTrue( findPath.getPathAsNodes() == null );
findPath = getFindPath( graph, "a", "b", 1 );
assertTrue( findPath.getPathAsNodes() != null );
findPath = getFindPath( graph, "a", "b", 0 );
assertTrue( findPath.getPathAsNodes() == null );
findPath = getFindPath( graph, "d", "a", 3 );
assertTrue( findPath.getPathAsNodes().size() == 4 );
findPath = getFindPath( graph, "d", "b", 2 );
assertTrue( findPath.getPathAsNodes().size() == 3 );
assertTrue( findPath.getPathAsRelationships().size() == 2 );
assertTrue( findPath.getPath().size() == 5 );
}
/**
* /--2--A--7--B--2--\ S E \----7---C---7----/
*/
public void testFindPathMoreComplex()
{
graph.makeEdge( "s", "c", "cost", (double) 7 );
graph.makeEdge( "c", "e", "cost", (double) 7 );
graph.makeEdge( "s", "a", "cost", (double) 2 );
graph.makeEdge( "a", "b", "cost", (double) 7 );
graph.makeEdge( "b", "e", "cost", (double) 2 );
FindSingleShortestPath findPath = getFindPath( graph, "s", "e",
Integer.MAX_VALUE );
assertTrue( findPath.getPathAsNodes() != null );
assertTrue( findPath.getPathAsNodes().size() == 3 );
}
/**
* /--2--A--7--B--2--\ S E \----7---C---7----/
*/
public void testPathConstruct()
{
graph.makeEdge( "s", "a", "cost", (double) 1 );
graph.makeEdge( "a", "b", "cost", (double) 1 );
graph.makeEdge( "a", "c", "cost", (double) 1 );
graph.makeEdge( "b", "d", "cost", (double) 1 );
graph.makeEdge( "d", "e", "cost", (double) 1 );
graph.makeEdge( "c", "e", "cost", (double) 1 );
graph.makeEdge( "b", "f", "cost", (double) 1 );
graph.makeEdge( "d", "f", "cost", (double) 1 );
graph.makeEdge( "e", "f", "cost", (double) 1 );
FindSingleShortestPath findPath = getFindPath( graph, "s", "f",
Integer.MAX_VALUE );
assertPath( findPath, graph, "s", "a", "b", "f" );
}
public void testSwitchDepths()
{
graph.makeEdge( "big", "a" );
graph.makeEdge( "big", "b" );
graph.makeEdge( "big", "c" );
graph.makeEdge( "big", "d" );
graph.makeEdge( "big", "e" );
graph.makeEdge( "big", "f" );
graph.makeEdge( "a", "g" );
graph.makeEdge( "a", "h" );
graph.makeEdge( "b", "i" );
graph.makeEdge( "b", "j" );
graph.makeEdge( "c", "k" );
graph.makeEdge( "d", "l" );
graph.makeEdge( "g", "m" );
graph.makeEdge( "g", "n" );
graph.makeEdge( "n", "o" );
graph.makeEdge( "o", "small" );
graph.makeEdge( "small", "p" );
// This should make the finder switch depths so that the one with
// least relationships ("big" or "small"; "small" in this case)
// will go deepest. But how do we make sure?
FindSingleShortestPath finder = getFindPath( graph, "small", "big", 5 );
assertPath( finder, graph, "small", "o", "n", "g", "a", "big" );
}
private void assertPath( FindSingleShortestPath finder,
SimpleGraphBuilder graph, String... path )
{
assertEquals( path.length, finder.getPathAsNodes().size() );
int counter = 0;
for ( Node pathNode : finder.getPathAsNodes() )
{
Node graphNode = graph.getNode( path[ counter++ ] );
assertEquals( graphNode.getProperty( SimpleGraphBuilder.KEY_ID ) +
", " + pathNode.getProperty( SimpleGraphBuilder.KEY_ID ),
graphNode, pathNode );
}
}
}