Added Graph Color tester

package edu.bu.ec504.hw2.p1;

import edu.bu.ec504.hw2.p1.edges.UndirectedEdge;

import edu.bu.ec504.hw2.p1.graphs.EdgeListGraph;

import edu.bu.ec504.hw2.p1.graphs.Graph;

import edu.bu.ec504.hw2.p1.support.Color;

import edu.bu.ec504.hw2.p1.vertices.ColoredVertex;

import static edu.bu.ec504.hw2.p1.GraphColorer.color;

public class GraphColorerTester {

    public static void main(String[] args) {

        Graph<ColoredVertex, UndirectedEdge<ColoredVertex>> G = new EdgeListGraph<ColoredVertex, UndirectedEdge<ColoredVertex>>();

        // Build a K_{3,3}

        ColoredVertex[] partA = {

                ColoredVertex.of(Color.first()),

                ColoredVertex.of(Color.first()),

                ColoredVertex.of(Color.first()),

        };

        ColoredVertex[] partB = {

                ColoredVertex.of(Color.first()),

                ColoredVertex.of(Color.first()),

                ColoredVertex.of(Color.first()),

        };

        // build the graph

        // ... vertices

        for (ColoredVertex v : partA) {

            G.addVertex(v);

        }

        for (ColoredVertex v : partB) {

            G.addVertex(v);

        }

        // ... edges

        for (ColoredVertex v : partA)

            for (ColoredVertex w : partB) {

                G.addEdge(UndirectedEdge.of(v,w));

            }

        // color it

        int col = color(G);

        System.out.println("Colored with: "+col+" colors.");

        System.out.println(G);

        if (col!=2) {

            throw new RuntimeException("Coloring is wrong - should be 2 but got "+col);

        }

    }

}