diff --git a/cs621/proj4/KnightsTourBoard.java b/cs621/proj4/KnightsTourBoard.java
index 5f6e18b..a01697e 100644
--- a/cs621/proj4/KnightsTourBoard.java
+++ b/cs621/proj4/KnightsTourBoard.java
@@ -8,9 +8,6 @@ public class KnightsTourBoard
     KnightsTourBoard(int width, int height)
     {
         m_board = new int[width][height];
-        for (int x = 0; x < m_width; x++)
-            for (int y = 0; y < m_height; y++)
-                m_board[x][y] = 0;
     }
 
     public int getWidth() { return m_width; }
@@ -19,6 +16,9 @@ public class KnightsTourBoard
 
     public boolean tour(int startx, int starty)
     {
+        for (int x = 0; x < m_width; x++)
+            for (int y = 0; y < m_height; y++)
+                m_board[x][y] = 0;
         m_board[startx][starty] = 1;
         return tourFrom(2, startx, starty);
     }
diff --git a/cs621/proj4/KnightsTourBoardTest.java b/cs621/proj4/KnightsTourBoardTest.java
new file mode 100644
index 0000000..87086be
--- /dev/null
+++ b/cs621/proj4/KnightsTourBoardTest.java
@@ -0,0 +1,33 @@
+
+import junit.framework.TestCase;
+
+public class KnightsTourBoardTest extends TestCase
+{
+    public void testKnightsTourBoardImpossible1()
+    {
+        KnightsTourBoard ktb = new KnightsTourBoard(3, 3);
+
+        assertFalse(ktb.tour(0, 0));
+        assertFalse(ktb.tour(1, 1));
+        assertFalse(ktb.tour(0, 1));
+    }
+
+    public void testKnightsTourBoardImpossible2()
+    {
+        KnightsTourBoard ktb = new KnightsTourBoard(3, 4);
+
+        assertFalse(ktb.tour(0, 0));
+        assertFalse(ktb.tour(1, 1));
+        assertFalse(ktb.tour(0, 1));
+        assertFalse(ktb.tour(1, 2));
+        assertFalse(ktb.tour(1, 3));
+        assertFalse(ktb.tour(2, 3));
+    }
+
+    public void testKnightsTourBoardPossible1()
+    {
+        KnightsTourBoard ktb = new KnightsTourBoard(5, 5);
+
+        assertTrue(ktb.tour(2, 2));
+    }
+}
diff --git a/cs621/proj4/Makefile b/cs621/proj4/Makefile
index a9153ee..98cc97f 100644
--- a/cs621/proj4/Makefile
+++ b/cs621/proj4/Makefile
@@ -1,4 +1,6 @@
 
+export CLASSPATH := $(CLASSPATH):/usr/share/junit/lib/junit.jar
+
 all: $(patsubst %.java,%.class,$(wildcard *.java))
 
 %.class: %.java
@@ -9,6 +11,10 @@ javadoc:
 	-mkdir doc
 	javadoc -d doc *.java
 
+.PHONY: test
+test: all
+	java junit.swingui.TestRunner KnightsTourBoardTest
+
 clean:
 	-rm -f *.class
 	-rm -rf doc