/*
* SchemaCrawler
* Copyright (c) 2000-2013, Sualeh Fatehi.
*
* Licensed 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 schemacrawler.test;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
import java.util.Arrays;
import org.junit.Test;
import sf.util.DirectedGraph;
import sf.util.GraphException;
public class DirectedGraphTest
{
@Test
public void cycles()
throws Exception
{
final DirectedGraph<String> graph = makeGraph();
assertFalse(graph.containsCycle());
graph.addDirectedEdge("C", "A");
assertTrue(graph.containsCycle());
}
@Test
public void smallCycle()
throws Exception
{
final DirectedGraph<String> graph = new DirectedGraph<>();
assertFalse(graph.containsCycle());
graph.addDirectedEdge("A", "B");
graph.addDirectedEdge("B", "A");
assertTrue(graph.containsCycle());
}
@Test
public void subGraph()
throws Exception
{
final DirectedGraph<String> graph = makeGraph();
graph.addDirectedEdge("C", "F");
graph.addDirectedEdge("B", "G");
graph.addDirectedEdge("D", "F");
assertFalse(graph.containsCycle());
assertEquals("[B, C, G, F]", graph.subGraph("B").topologicalSort()
.toString());
assertEquals("[C, F]", graph.subGraph("C").topologicalSort().toString());
assertEquals("[E]", graph.subGraph("E").topologicalSort().toString());
assertEquals("[B, C, G, F]", graph.subGraph("B", -1).topologicalSort()
.toString());
assertEquals("[B]", graph.subGraph("B", 0).topologicalSort().toString());
assertEquals("[B, C, G]", graph.subGraph("B", 1).topologicalSort()
.toString());
assertEquals("[B, C, G, F]", graph.subGraph("B", 2).topologicalSort()
.toString());
assertEquals("[B, C, G, F]", graph.subGraph("B", 3).topologicalSort()
.toString());
}
@Test
public void topologicalSort()
throws Exception
{
for (int i = 0; i < 8; i++)
{
final DirectedGraph<String> graph = makeGraph();
assertEquals("Test run #" + (i + 1), "[A, E, B, D, C]", graph
.topologicalSort().toString());
}
}
@Test(expected = GraphException.class)
public void topologicalSortCyclical()
throws Exception
{
final DirectedGraph<String> graph = makeGraph();
graph.addDirectedEdge("C", "A");
assertEquals(Arrays.asList("E", "A", "D", "B", "C"), graph
.topologicalSort().toString());
}
private DirectedGraph<String> makeGraph()
{
final DirectedGraph<String> graph = new DirectedGraph<String>()
{
{
addDirectedEdge("A", "B");
addDirectedEdge("B", "C");
addDirectedEdge("A", "D");
addVertex("E");
}
};
return graph;
}
}