added new test cases

test/com/jwetherell/algorithms/data_structures/test/DisjointSetTests.java

@@ -1,5 +1,7 @@
 package com.jwetherell.algorithms.data_structures.test;
 
+import static org.junit.Assert.assertTrue;
+
 import org.junit.Assert;
 import org.junit.Test;
 
@@ -136,4 +138,48 @@ private static final String toString(DisjointSet.Item<Integer>[] items) {
         builder.append("}\n");
         return builder.toString();
     }
-}
+
+    @Test
+    public void testDisjointSet3() {
+    	final int max = 10;
+        final int[] array = new int[max];
+        for (int i=0; i<array.length; i++)
+            array[i] = i+1;
+
+        final DisjointSet.Item<Integer>[] items = new DisjointSet.Item[array.length];
+        for (int i=0; i<items.length; i++) {
+            final int v = array[i];
+            final DisjointSet.Item<Integer> s = DisjointSet.makeSet(v);
+            items[i] = s;
+        }
+
+        final int half = items.length/2;
+
+        // first half set
+        DisjointSet.Item<Integer> first = items[0];
+        for (int i=1; i<half; i++) {
+            final DisjointSet.Item<Integer> item = items[i];
+            first = DisjointSet.union(item, first);
+        }
+
+        final DisjointSet.Item<Integer> nullValue = DisjointSet.find(null);
+        Assert.assertTrue(nullValue==null);
+
+        final DisjointSet.Item<Integer> xyNull = DisjointSet.union(null, null);
+        Assert.assertTrue(xyNull==null);
+
+        final DisjointSet.Item<Integer> xNull = DisjointSet.union(null, first);
+        Assert.assertTrue(xNull.getValue()==first.getValue());
+
+        final DisjointSet.Item<Integer> yNull = DisjointSet.union(first, null);
+        Assert.assertTrue(yNull.getValue()==first.getValue());
+
+        String fresult = first.toString();
+        String expectedResult = "parent=2 rank=1 value=2";
+        assertTrue(fresult.equals(expectedResult));
+
+        String temp = "Sample";
+        Boolean result = first.equals(temp);
+        assertTrue(!result);
+    }
+}

test/com/jwetherell/algorithms/data_structures/test/GraphTests.java

@@ -127,4 +127,60 @@ public void testCostPathPair() {
         Assert.assertTrue(p2.equals(p3) && p2.hashCode()==p3.hashCode());
         Assert.assertTrue(p3.equals(p2) && p3.hashCode()==p2.hashCode());
     }
-}
+
+    @Test
+    public void testGraphtoString() {
+    	Graph g1 = new Graph();
+
+    	final List<Vertex<Integer>> vertices = new ArrayList<Vertex<Integer>>();
+        final Vertex<Integer> p1 = new Vertex<Integer>(10,1);
+        vertices.add(p1);
+        final Vertex<Integer> p2 = new Vertex<Integer>(10,2);
+        vertices.add(p2);
+
+        final List<Edge<Integer>> edges = new ArrayList<Edge<Integer>>();
+        final Edge<Integer> e1 = new Edge<Integer>(1,p1,p2);
+        edges.add(e1);
+        final Edge<Integer> e2 = new Edge<Integer>(1,p2,p1);
+        edges.add(e2);
+
+    	Graph g2 = new Graph(vertices, edges);
+    	List got_e1 = g2.getEdges();
+
+    	Integer temp = 1;
+    	g1.toString();
+
+    	p1.getValue();
+    	p1.getWeight();
+    	p1.setWeight(5);
+    	p1.getEdge(p2);
+    	p1.pathTo(p2);
+    	p1.toString();
+    	p1.compareTo(p2);
+
+    	Edge<Integer> e3 = new Edge<Integer>(e1);
+    	e1.getCost();
+    	e1.setCost(0);
+
+    	Graph.CostVertexPair<Integer> c1 = new Graph.CostVertexPair<Integer>(1, new Vertex<Integer>(10));
+        Graph.CostVertexPair<Integer> c2 = new Graph.CostVertexPair<Integer>(1, new Vertex<Integer>(11));
+        Graph.CostVertexPair<Integer> c3 = new Graph.CostVertexPair<Integer>(1, new Vertex<Integer>(9));
+    	c1.getCost();
+    	c1.setCost(5);
+    	c3.setCost(50);
+    	c1.getVertex();
+    	c1.compareTo(c2);
+    	c1.compareTo(c3);
+    	c1.toString();
+
+    	final List<Edge<Integer>> s1 = new ArrayList<Graph.Edge<Integer>>(3);
+        s1.add(new Edge<Integer>(1, new Vertex<Integer>(10), new Vertex<Integer>(20)));
+        s1.add(new Edge<Integer>(2, new Vertex<Integer>(20), new Vertex<Integer>(30)));
+        final Graph.CostPathPair<Integer> cp1 = new Graph.CostPathPair<Integer>(1, s1);
+        cp1.getCost();
+        cp1.setCost(0);
+    	cp1.toString();
+
+    	Assert.assertFalse(g2.equals(temp));
+    }
+}