Computer Science Department, Bucknell University

CSCI 475 JUnit - Unit Testing in Java
Sample Program to Demo JUnit
Fall 2004
Professor Dan Hyde

  1. Make sure the CLASSPATH variable in your .cshrc file is correct. If you have two CLASSPATH lines, you must remove the old one or combine them.
    setenv JUnitDIR /usr/local/junit
    ### CLASSPATH - environment variable for JAVA
    setenv CLASSPATH .:$JUnitDIR/junit.jar
  2. Create a new directory and copy and paste the following into two new files called and
    //----------- code for ----------
    // Latitude class developed using Unit Testing and JUnit
    // By Dan Hyde September 25, 2002
    import javax.swing.*;
    public class Latitude{
        private double deg;
        private double min;
        private double sec;
        private String hemi;  // hemisphere "N" or "S"
        public Latitude(){
    	deg = 0.0;
    	min = 0.0;
    	sec = 0.0;
    	hemi = "N";
        public Latitude(double d, double m, double s, String h){
    	deg = d;
    	min = m;
    	sec = s;
    	hemi = h;
        // more sophisticated than you need do!
        public boolean equals(Object anObject){
    	if( !(anObject instanceof Latitude) ) // needs ()s after !
    	    return false;
    	Latitude aLatitude = (Latitude) anObject;
    	if(deg == aLatitude.deg && min == aLatitude.min && 
    	   sec == aLatitude.sec){
    		return true;
    	    if(deg == 0.0 && min == 0.0 && sec == 0.0)
    		return true;
    	return false;
    //--------------- code for file ------------
    // LatitudeTest class for JUnit
    // By Dan Hyde September 25, 2002, Update September 22, 2004
    // Assumes Latitude class has a default constructor, a four argument
    // constructor and an equals method.  Much missing of the final class!
    // Enter "LatitudeTest" in field when you run "java test.ui.TestRunner"
    import junit.framework.*;  // need to import test framework
    public class LatitudeTest extends TestCase{
        private Latitude N0;
        private Latitude N90;
        public LatitudeTest(String name) { // need a constructor with String arg 
        protected void setUp(){
    	N0 = new Latitude();
    	N90 = new Latitude(90.0, 0.0, 0.0, "N");
        public void testLatitudeConst(){
            // O degrees N from default constructor should equal 
            // 0 degrees N from 4 arg constructor
    	Latitude N0expected = new Latitude(0.0, 0.0, 0.0, "N");
    	// To check if true use	assertTrue()
    	// DONT'T use assert() which is in old articles!
    	assertTrue( N0.equals( N0expected ) );
            // 0 degrees N should be equal to 0 degrees S.
    	Latitude S0expected = new Latitude(0.0, 0.0, 0.0, "S");
    	// To check if equal use assertEquals()
    	assertEquals( N0, S0expected );
        public static Test suite(){
    	TestSuite suite = new TestSuite();
    	suite.addTest( new LatitudeTest("testLatitudeConst") );
    	return suite;
  3. Compile both files
        altair{224}% javac
        altair{225}% javac

  4. Run the tester in text mode
        altair{226}% java junit.textui.TestRunner LatitudeTest
    or in graphical mode
        altair{227}%java junit.swingui.TestRunner LatitudeTest
    In graphical mode, you should see a green bar indicating the test was successful. The class name LatitudeTest is optional in the graphical mode. It is required in the text mode.

    Note that you need two files - one with the class you are developing and the second class for the unit tests.

Page maintained by Dan Hyde, hyde at Last update September 22, 2004
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