JUNIT in Eclipse

PepperCredit to Eclipse Documentation

http://help.eclipse.org/juno/index.jsp?topic=%2Forg.eclipse.jdt.doc.user%2FgettingStarted%2Fqs-junit.htm

Purpose

• Create test case classes to test individual classes or small groups– Easy to hook test classes to the classes being

tested

• Test building tools inside Junit class• Easy to rerun one set of tests or all tests in the

entire system.• Easy to supress tests in production

Startup

• Create a project if you do not have one (file -> New -> Project)

• Create a folder for your test cases (optional) • Create a test case for a class you intend to

write (file -> new -> Junit Test Case)• Choose the type (new junit4 test) and name

your test class• You can indicate the name of the class being

tested, but only after it is created

Test Case Creation Screen

How to Create a Test Method

• Type @Test to override the test method• Type test method header -> public void

test2() • Code the test to just invoke the fail method

public void testFailure() throws Exception { fail();}

Running a test method

• Hit the run button. – Or Run as -> Junit test on

project or class• Junit Test runs• See results in JUnitView– Failure tab– Tab for all tests as a tree– * = changed code after running

test

Test Result Checking

http://www.vogella.com/tutorials/JUnit/article.html•assertEquals() : object comparison using equals method•assertTrue() / assertFalse() : compare to boolean value•assertNull() / assertNotNull() : is the variable null•assertSame() / assertNotSame(): reference same object address•assertThat - uses matcher

Let's Try• Write a simple class to be tested:package testProject;

public class aprogram {int x = 1;public int myfun (int y){x = x + 1; return x;}

}

Now code a few testspackage JUnitTest;import static org.junit.Assert.*;import org.junit.Test;import testProject.aprogram;

public class TestFailure {

@Testpublic void test1() {

aprogram a = new aprogram();aprogram b = new aprogram(); assertTrue( b.myfun(3) == 2 );assertTrue( a.myfun(3) == 3 );

}@Testpublic void test2() {

//fail("Not yet implemented");aprogram a = new aprogram();aprogram b = new aprogram();assertTrue( b.myfun(3) == 4 );//assertTrue( a.myfun(3) == 1 );

}}

Run the Tests

• See how it points to problem test• See how one failure in a test class stops the

running of the next one• Make both succeed• Make both fail

Create a Test Suite

• File -> New -> Java -> Junit -> Junit Test Suite • Name the suite (AllTests)• Select test classes to run