1. Credit to Eclipse Documentation
JUNIT in Eclipse
Pepper
Credit to Eclipse Documentation

2. 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

3. 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

4. Test Case Creation Screen

5. How to Create a Test Method
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(); }

6. Running a test method Hit the run button. Junit Test runs
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

7. Test Result Checking
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

8. 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; }

9. Now code a few tests
package JUnitTest; import static org.junit.Assert.*; import org.junit.Test; import testProject.aprogram; public class TestFailure public void test1() { aprogram a = new aprogram(); aprogram b = new aprogram(); assertTrue( b.myfun(3) == 2 ); assertTrue( a.myfun(3) == 3 ); } public void test2() { //fail("Not yet implemented"); assertTrue( b.myfun(3) == 4 ); //assertTrue( a.myfun(3) == 1 );

10. 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

11. Create a Test Suite
File -> New -> Java -> Junit -> Junit Test Suite
Name the suite (AllTests)
Select test classes to run