this is an assignement question from software engineering course and its a text book question..need help with the assignement as soon as possible!! please!and the textbook is fundamentals of software engineering second addition by carlo ghezzi and mehdi

JUnit

CSI 5390

Department of Computer Science and Engineering

Oakland University

Dae-Kyoo Kim

JUnit: Overview

• A Java framework for writing and running unit tests – Test fixtures – Test cases – Test suites – Test runner

• By Kent Beck and Erich Gamma • Written with “test first” and pattern-based

development in mind – Tests written before code – Allows for regression testing – Facilitates refactoring

• JUnit is Open Source – www.junit.org – JUnit Version 4, released Mar 2006

Unit

Testing

Acceptance

Testing

Integration

Testing

System

Testing

JUnit Classes

*

Test

run(TestResult)

ConcreteTestCase

setUp()

tearDown()

runTest()

TestResult

TestCase

run(TestResult)

setUp()

tearDown()

testName:String

runTest()

TestSuite

run(TestResult)

addTest()

UnitToBeTested

Methods under Test

Design patterns in JUnit

Test

run(TestResult)

ConcreteTestCase

setUp()

tearDown()

runTest()

TestResult

TestCase

run(TestResult)

setUp()

tearDown()

testName:String

runTest()

TestSuite

run(TestResult)

addTest()

Command Pattern

TestedUnit

*

Design patterns in JUnit

Test

run(TestResult)

ConcreteTestCase

setUp()

tearDown()

runTest()

TestResult

TestCase

run(TestResult)

setUp()

tearDown()

testName:String

runTest()

TestSuite

run(TestResult)

addTest()

Composite

Pattern

TestedUnit

*

Design patterns in JUnit

Test

run(TestResult)

ConcreteTestCase

setUp()

tearDown()

runTest()

TestResult

TestCase

run(TestResult)

setUp()

tearDown()

testName:String

runTest()

TestSuite

run(TestResult)

addTest()

Template Method

Pattern

TestedUnit

*

Design patterns in JUnit

Test

run(TestResult)

ConcreteTestCase

setUp()

tearDown()

runTest()

TestResult

TestCase

run(TestResult)

setUp()

tearDown()

testName:String

runTest()

TestSuite

run(TestResult)

addTest()

Adapter

Pattern

TestedUnit

*

Example: Testing MyList

• Unit to be tested

– MyList

• Methods under test

– add()

– remove()

– contains()

– size()

• Concrete Test case

– MyListTestCase

Test

run(TestResult)

MyListTestCase

setUp()

tearDown()

runTest()

testAdd()

testRemove()

TestResult

TestCase

run(TestResult)

setUp()

tearDown()

testName:String

runTest()

TestSuite

run(TestResult)

addTest()

MyList

add()

remove()

contains()

size()

*

Writing TestCases in JUnit

public class MyListTestCase extends TestCase {

public MyListTestCase(String name) {

super(name);

}

public void testAdd() {

// Set up the test

List aList = new MyList();

String anElement = “a string”;

// Perform the test

aList.add(anElement);

// Check if test succeeded

assertTrue(aList.size() == 1);

assertTrue(aList.contains(anElement));

}

protected void runTest() {

testAdd();

}

}

Writing Fixtures and Test Cases public class MyListTestCase extends TestCase {

// …

private MyList aList;

private String anElement;

public void setUp() {

aList = new MyList();

anElement = “a string”;

}

public void testAdd() {

aList.add(anElement);

assertTrue(aList.size() == 1);

assertTrue(aList.contains(anElement));

}

public void testRemove() {

aList.add(anElement);

aList.remove(anElement);

assertTrue(aList.size() == 0);

assertFalse(aList.contains(anElement));

}

Test Fixture

Test Case

Test Case

Collecting TestCases into

TestSuites

public static Test suite() {

TestSuite suite = new TestSuite();

suite.addTest(new MyListTest(“testAdd”));

suite.addTest(new MyListTest(“testRemove”));

return suite;

}

*

jUnit 4 vs jUnit 3

• jUnit 4 is completely based on annotations

– No longer necessary to extend class TestCase

– Test-method names do not have to start with the prefix “test”.

– Instead they are annotated with the @Test annotation

13

jUnit 4 vs jUnit 3

jUnit 3

import

junit.framework.TestCase;

public class CalculatorTest

extends TestCase {

public void testadd() {

....

}

}

jUnit 4

import org.junit.Test;

public class CalculatorTest {

@Test public void add() {

....

}

}

Testing for Exceptions

jUnit 3

public class CalculatorTest { public void testDivideByZero() { try { int n = 2/0; fail(“Division by zero!”); } catch (ArithmeticException

success) { assertNotNull(Success.getMe ssage())}

} }

jUnit 4

public class CalculatorTest {

@Test(expected=ArithmeticEx ception.class)

public void DivideByZero() { int n = 2/0;

} }

Example

class Money {

private int fAmount;

private String fCurrency;

public Money(int amount, String currency) {

fAmount= amount;

fCurrency= currency;

}

public int amount() {

return fAmount;

}

public String currency() {

return fCurrency;

}

public Money add(Money m) {

return new Money(amount()+m.amount(), currency());

}

}

Unit Testing add()

import org.junit.Test; import static org.junit.Assert.*;

public class MoneyTest { @Test public void add() { Money m12CHF= new Money(12, "CHF"); Money m14CHF= new Money(14, "CHF"); Money expected= new Money(26, "CHF"); Money observed= m12CHF.add(m14CHF); assertTrue(expected.equals(observed));

} } Assertion: Returns True if parameter of

type Boolean evaluates to True

Annotations in jUnit 4.0

• @Test public void foo()

– Annotation @Test identifies that foo() is a test method

• @Test(expected=IllegalArgumentException.class)

– Tests if the test method throws the named exception

@Before and @After:

Ensuring Pre- and Post Conditions

• @Before public void bar() – Perform bar() before executing a test method

• @After public void foobar() – A test method must finish with call to foobar()

public class CalculatorTest {

@Test public void add()

@Test public void sub()

@Before public void setupTestData(){ } //executed before every add/sub

@After public void teardownTestData() {} //executed after every add/sub

}

• @BeforeClass public void foofoo() – Perform foofoo() before the start of all tests

– e.g., database connection

• @AfterClass public void blabla() – Perform blabla() after all tests have finished.

– e.g., database disconnection

public class CalculatorTest {

@BeforeClass // executed at instantiation of class

public static void setupDatabase Connection() { ... }

@AfterClass // executed after remove instance of class

public static void teardownDatabase Connection() { ... }

}

@BeforeClass and @AfterClass:

Ensuring Pre- and Post Conditions

@Test(timeout): Shortening

Tests

• Some tests take time (e.g., network connectivity)

– Set an upper bound for the test to expire

@Test(timeout=5000)

public void testLengthyOperation() {

...

}

Fails if taking longer

then 100 milliseconds

@Ignore: Omitting Tests

• @Ignore(string S) – Ignore the test method, print out the string S

– Useful when the code has been changed, but the test has not yet been adapted

– Useful when the current release of a third-party library used in the SUT has a bug

public class CalculatorTest {

@Ignore(“Don‘t run now this test until bug in Foo is fixed”)

@Test public void testSpecialFunctionality() {

...

}

}

Assertions in jUnit 4.0

• assertTrue(predicate); – Returns True if predicate evaluates to True

• assertTrue([message], boolean condition) – Check if the boolean condition is True

• fail(String) – Let the method fail. Useful to check that a certain part of the code is not reached.

• assertsEquals([message], expected, actual) – Returns message if the values are the same

• assertsEquals([message], expected, actual, tolerance) – Used for float and double; tolerance specifies the number of decimals which must

be the same

Assertions in jUnit 4.0

• assertNull([message], object) – Checks if the object is null and prints message if it is

• assertNotNull([message], object) – Check if the object is not null

• assertSame([message], expected, actual) – Check if both variables refer to the same object

• assertNotSame([message], expected, actual) – Check that both variables refer not to the same object

Example

import org.junit.Test;

import static org.junit.Assert.*;

public class CalculatorTest {

private int x = 1;

private int y = 1;

@Test public void add() {

int z = x + y;

assertEquals(2, z);

}

}

Additional Readings

• JUnit Website www.junit.org/index.htm