HINT: GraphUnitTests

import static org.junit.Assert.*;

import org.junit.Before;

import org.junit.Test;

import java.util.List;

import java.util.ArrayList;

public class GraphUnitTests {

Graph g1;

Graph g2;

    @Before

    public void init() 

    {

    initG1();

    initG2();

    }

    // graph from assignment page

    private void initG1() 

    {

    // make sure vertices start at 0

    DefaultGraphVertex.resetIDCounter();

    g1 = new DirectedGraph();

    // add 4 vertices

    for ( int i = 0; i < 4; i++ )

    {

    g1.addVertex(new DefaultGraphVertex());

    }

    // add the edges

    int[] sources = {0,1,1,2,3,3};

    int[] targets = {1,2,3,3,0,1};

    // for each edge

    for ( int i = 0; i < sources.length; i++ )

    {

    g1.addEdge(sources[i], targets[i]);

    }

    }

    // graph with traversals that are more interesting

    private void initG2() 

    {

// make sure vertices start at 0

    DefaultGraphVertex.resetIDCounter();

    g2 = new DirectedGraph();

    // add 4 vertices

    for ( int i = 0; i < 5; i++ )

    {

    g2.addVertex(new DefaultGraphVertex());

    }

    // add the edges

    int[] sources = {0,0,0,1,3,4};

    int[] targets = {1,2,4,3,4,1};

    // for each edge

    for ( int i = 0; i < sources.length; i++ )

    {

    g2.addEdge(sources[i], targets[i]);

    }

    }

    @Test

    public void numVerticesTest() {

    // the number of vertices is 4

    assertEquals("number of vertices test", 4, g1.numVertices());

    }

    @Test

    public void numEdgesTest() {

    // the number of edges is 6

    assertEquals("number of edges test", 6, g1.numEdges());

    }

    @Test

    public void addVertexTest() {

    g1.addVertex(new DefaultGraphVertex());

    // the number of vertices is now 5

    assertEquals("add vertex test", 5, g1.numVertices());   

    }

    @Test

    public void graphStringTest() {

    System.out.println(g1.toString());

    assertEquals("graph string test", "((0,1,2,3),(0->1,1->2,1->3,2->3,3->0,3->1))", 

    g1.toString());   

    }

    @Test

    public void df1_0Test() {

    int[] traversalOrder = {0,1,2,3};

    List<GraphVertex> traversal = createTraversalList( g1, traversalOrder );

    System.out.println( "traversal is: " + g1.depthFirst(0).toString());

    assertEquals("DF traversal from 0 in G1 test", traversal, g1.depthFirst(0));

    }

    @Test

    public void df1_2Test() {

    int[] traversalOrder = {2,3,0,1};

    List<GraphVertex> traversal = createTraversalList( g1, traversalOrder );

    System.out.println( "traversal is: " + g1.depthFirst(2).toString());

    assertEquals("DF traversal from 2 in G1 test", traversal, g1.depthFirst(2));

    }

    @Test

    public void bf1_0Test() {

    int[] traversalOrder = {0,1,2,3};

    List<GraphVertex> traversal = createTraversalList( g1, traversalOrder );

    System.out.println( "traversal is: " + g1.breadthFirst(0).toString());

    assertEquals("BF traversal from 0 in G1 test", traversal, g1.breadthFirst(0));

    }

    @Test

    public void bf1_2Test() {

    int[] traversalOrder = {2,3,0,1};

    List<GraphVertex> traversal = createTraversalList( g1, traversalOrder );

    System.out.println( "traversal is: " + g1.depthFirst(0).toString());

    assertEquals("BF traversal from 2 in G1 test", traversal, g1.breadthFirst(2));

    }

    @Test

    public void df2_0Test() {

    int[] traversalOrder = {0,1,3,4,2};

    List<GraphVertex> traversal = createTraversalList( g2, traversalOrder );

    System.out.println( "traversal is: " + g2.depthFirst(0).toString());

    assertEquals("DF traversal from 0 in G2 test", traversal, g2.depthFirst(0));

    }

    @Test

    public void bf2_0Test() {

    int[] traversalOrder = {0,1,2,4,3};

    List<GraphVertex> traversal = createTraversalList( g2, traversalOrder );

    System.out.println( "traversal is: " + g2.breadthFirst(0).toString());

    assertEquals("DF traversal from 0 in G2 test", traversal, g2.breadthFirst(0));

    }

    /**

     * Helper method to create a list of GraphVertex objects corresponding

     * to the traversal order (of IDs) given.

     */

    private List<GraphVertex> createTraversalList( Graph g, int[] traversalOrder )

    {

    // for the traversal

    List<GraphVertex> traversal = new ArrayList<GraphVertex>();

    // for each ID in the traversalOrder array

    for ( int i = 0; i < traversalOrder.length; i++ )

    {

    // add the corresponding GraphVertex object

    traversal.add( g.getVertex( traversalOrder[i] ) );

    }

    // return the list

    return traversal;

    }

}