Download JUnit

JUnit
Eclipse, Java and introduction
to Junit
Topics Covered
Using Eclipse IDE
 Example Java Programs
 Junit Introduction

What is Eclipse?
Eclipse is an open source community whose projects are
focused on providing an extensible development platform
and application frameworks for building software.
Download eclipse from
http://www.eclipse.org/downloads/index.php
Article on using junit with Eclipse
http://www.onjava.com/pub/a/onjava/2004/02/04/juie.html
Java
Java Tutorials
 http://java.sun.com/docs/books/tutorial/
getStarted/index.html
Thinking in Java 3rd Edition by Bruce
Eckel
 http://www.mindview.net/Books/TIJ/
Or get a printed version
A simple java Program
//A Very Simple Example - Hello.java
public class Hello {
public static void main(String[] args) {
System.out.println(“Hello world");
}
}
Example Compilation
#bash# javac Hello.java
#bash# java Hello
Hello world
Compiling the Eclipse
Way
Step 1: Create a New Project.
 Click on File -> New Project
 Select Java Project
 Enter the name for the project
Step 2: Create a Class File
 Click on File -> New Class
 Enter the name for the Class (Hello)
Compiling the Eclipse
Way (Contd.)
Step 3: Copy or create the java program
(Hello.java) and Save.
Step 4: Run the application
 Select Run -> Run and click on Java
Application.
 Click on the New button and then Click
on Run.
Eclipse Output
What is Unit Test?

A definition from IEEE
– Testing of individual hardware or software
or group of related units
 Usually,
a unit test is code that tests a "unit":
the unit could be a class, a component, a
module, a function
 Unit Test usually built and run at the
development cycle.
 Unit test is not functional, application testing
 Unit tests are not interactive
We need a framework

A unit testing framework provides
A
mechanism to organize and group multiple
tests
 A simple way to invoke tests
 Clear indication of which tests passed/failed
 A standard way to write tests and specify
expected results.
What is JUnit




JUnit is a Unit Testing Tool for Java
JUnit is a regression testing framework
Programmed by Erich Gamma and Kent
Beck
Open Source
–
–
–
–
Hosted on SourceForge
http://sourceforge.net/index.php
http://junit.sourceforge.net/
http://www.junit.org/
JUnit’s Features
Assertions for testing expected results
 Testing fixtures for sharing common
test data
 Test suites for easily organizing and
running tests
 Graphical and textual test runners

JUnit Framework
junit.framework
<< interface >>
Test
Assert
run()
assertTrue()
assertEquals()
...
TestResult
TestCase
fName
setUp()
runTest()
tearDown()
run()
junit.textui.TestRunner
*
TestSuite
run()
addTest()
junit.swingui.TestRunner
http://junit.sourceforge.net/javadoc/index.html
How to Test with JUnit?
junit
TestCase
Student
1..*
exercise
TestStudent
test1
test2
…
TestRunner
1..*
run
Another Java Example
public class Student
{
private String sname;
private String sid;
private int score;
public Student(String num, String nam, int scr)
{
sid = num;
sname = nam;
score = scr;
}
Another Example(cont.)
public String getNumber()
{
return sid;
}
public String getName()
{
return sname;
}
public int getScore()
{
return score;
}
Another Example(cont.)
public void setNumber(String num)
{
sid = num;
}
public void setName(String name)
{
sname=name;
}
public void setScore(int scr)
{
score=scr;
}
} //End Class Student
Testing the Student
Class
public class TestStudent
{
public static void main(String[] args) {
Student student=new Student(“043”, “Justin”,100);
if (!(student.getName()!=null &&
student.getName().equals(“Justin”)))
System.out.println(“getName method failure”);
}
}
Testing the Junit way
import junit.framework.*;
public class TestStudent1 {
public static void main(String[] args) {
Student student = new Student(“043", "Justin",
100);
Assert.assertEquals("getName method failure",
"Justin", student.getName());
}
}
Assert in Junit
Class Assert provide a set of methods
 These methods are static
 They can throw an object with failure
messages.

– Messages are only displayed when an
assert fails
Junit TestCase
public class TestIt extends TestCase {
public TestIt (String name) {
super (name);
}
public void testGetMethod() {
Student student=new Student(“013", "Justin",
100);
assertEquals(“013", student.getNumber());
assertEquals("Justin", student.getName());
assertEquals(100, student.getScore());
}
}
Junit in Eclipse
Click on File -> New -> Junit Testcase
 Give the name for the testcase and
create/copy the file in the editor.
 Click on Run -> Run. Select Junit
Testcase, New and click on Run.

Junit in Eclipse
Assert.assertEquals
assertEquals can be overrided many
times for different comparison, such as
for String, int
 For object comparison, you have to
override equals in order to compare
fields of two objects

Equals in our example
public boolean equals(Object anObject)
{
if (anObject instanceof Student)
{
Student aStudent=(Student) anObject;
return
aStudent.getNumber().equals(getNumber())&&
aStudent.getName()==getName()&&aStudent.getS
core==getScore();
}
return false;
}
JUnit Rules and
Conventions

Subclass TestCase

Test methods
– public void testXXX() [throws …]
– Any number of assertions per method