Junit Final

7/30/2019 Junit Final

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CSE 4415 Day 2 Copyright © 2009 Nawwar Kabbani 1

Software Testing 2

Unit Testing

with

JUnit 4

Cem Kaner

Nawwar Kabbani

August 2009




JUnit

Unit testing framework for Java.

Based on a collection of Unit Testing frameworks called xUnit.

Adapted from SUnit (proposed by Kent Beck for Smalltalk)

Ported to other languages: C# (NUnit), Python (PyUnit), Javascript (JSUnit), Perl (Test::Class & Test::Unit)

Currently version 4.x, however JUnit 3.8 is still widely used.

JUnit 4 requires Java 1.5 at least, because it depends on Java“Annotations”.




First example

import org.junit.Test; // for @Test

import static org.junit.Assert.*; // assertEquals()

public class ArithmeticTest {

@Testpublic void addition() {

assertEquals(2, 1 + 1);

}

}


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Compare to JUnit 3

import junit.framework.TestCase;

public class ArithmeticTest extends TestCase {

public void testAddition() {

assertEquals(2, 1 + 1); // inherited from TestCase}

}


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Notes JUnit 4 automatically recognizes test methods preceded by

@Test annotation.

There is no need for main() to run the tests (see next slides forrunning JUnit tests).

Test methods must be public , void , with no parameters.

Test Method does not have to prefixed with 'test' (as in JUnit 3).

It's strongly recommended to separate the test class from theproduction class, although it's technically possible to combinethem in the same class in JUnit 4. Combining them *might* beuseful to test private methods and variables and is useful fortesting protected methods and variables.




JUnit tests output




JUnit tests output




JUnit tests output•Runs

•

Total number of tests run•Failures

• Tests that failed. For example assertions that failed.

•Errors

• Tests that generated unhandled (unexpected) exceptions.•Time elapsed (ms)




How do I run JUnit tests?

Command Line JUnit 3

java junit.textui.TestRunner TestClass

JUnit 4 java org.junit.runner.JUnitCore TestClass

Remember to make sure junit.jar is in the current path or inthe CLASSPATH environment variable. Or you can manuallyinclude its path in the java command:

Unix:

java -cp .:/path/to/junit.jar org.junit.runner.JUnitCore TestClass

Windows:java -cp .;c:\path\to\junit.jar org.junit.runner.JUnitCore TestClass




How do I run JUnit tests

Eclipse

1. Add JUnit Library to the project if it is not already there:

– Right-click on the project → Build Path → Add

Libraries...→

JUnit2. Run the unit tests

– Right-click → Run As → JUnit Test

Java code (invoke the tests from your program)

org.junit.runner.JUnitCore.runClasses(TestClass1.class, ...);




org.junit.Assert.* static methods

assertEquals (expected , actual ) Works with object, int, long, byte, string, … etc.

Object: it invokes object.equals(object) to check for equality.

assertEquals (expected , actual , εpsilon) // for float and double.

assertTrue / assertFalse (bool )

assertNull / assertNotNull (object)

assertSame / assertNotSame (object, object)

assertArrayEquals (object[], object[])

assertThat (object, [JMock epression])

For all assertXXX except assertThat(), you can specify an optionalcustom error message as a first parameter




Examples

assertEquals(“x must be 5, but it's not!”, 5, x);

String x = “Hello”, y = “ world”;

assertNotSame(“Hello world”, x + y);

Eq. to: assertFalse(“Hello world” == (x+y));

assertEquals(“Hello world”, x + y);

Eq. to: assertTrue(“Hello world”.equals(x + y));

assertEquals(2.0, Math.sqrt(4.0), 1e-10);




The “flexible” assertThat()

New assertion mechanism introduced by JMock.

More readable expressions, and more friendly/informative failuremessages.

Can be extended to create your own custom matchers. Ability to use boolean operators (and, or, not) to create complex

test expressions.




AssertThat examples

import static org.hamcrest.CoreMatchers.*;

assertThat(x, is(3));

assertThat(x, is(not(4)));

assertThat(myList, hasItem ("hello"));

assertThat(“Hello”, is(String.class));

y = x = new object();

assertThat(x, sameInstance(y));

assertThat(null, nullValue());

assertThat(d, allOf(notNullValue(),

instanceOf(Date.class));

x = “hello world”;

assertThat(x, anyOf(containsString(“hello"),

containsString(“hi")));

assertThat(x, either(containsString("hello"))

.or(containsString("hi")));




Other JUnit Annotations

@Before, @After: Initialization/Finalization code that has to berun before/after each test.

(cf. setUp(), tearDown() methods in JUnit 3).

@BeforeClass, @AfterClass: Code to be run before/after all of the tests. Methods with these annotations must be static.

@Ignore: skip the following test.

@Test(timeout = [x]): fail if the test took more than [x]milliseconds




Examplesclass ListTest {

private ArrayList<String> myList;

@Before

public void setUp() {

myList = new ArrayList<String>();

}

@Test public void addElement() {

myList.add(“hello”);

assertEquals(1, myList.size());

assertEquals(“hello”, myList.get(0));

}

@Test public void emptyList() {

AssertEquals(0, myList.size());

}

}




Examples

@Ingore(“Not ready”);@Test

public void newTest() {

fail(“This message won't show up”);

}

@Test(timeout = 1000) // fail if passed 1000ms public void tcpConnect() {

tcpSocket.open();

}




Testing Exceptions

@Test(expected = ExceptionClass.class)

The test passes if the expected exception is thrown, and failsotherwise.

JUnit 3 way:

@Test(expected = ArithmeticException.class)

public void divide() {int x = 10 / 0;

}

public void testException() {

try {

int x = 10 / 0;

fail(“Division by zero exception was expected!”);

}

catch (ArithmeticException e) { /* Pass! */ }

}




More resources• Official site: www.junit.org

•

JUnit Javadoc: http://junit.org/junit/javadoc/4.5/• JUnit cook book http://junit.sourceforge.net/doc/cookbook/cookbook.htm (one recipelong!)

•http://pub.admc.com/howtos/junit4x/junit4x.html

•http://supportweb.cs.bham.ac.uk/documentation/tutorials/docsystem/build/tutorials/junit/junit.html (JUnit 3 tutorial)

http://www.junit.org/

http://junit.org/junit/javadoc/4.5/

http://junit.sourceforge.net/doc/cookbook/cookbook.htm

http://pub.admc.com/howtos/junit4x/junit4x.html

http://supportweb.cs.bham.ac.uk/documentation/tutorials/docsystem/build/tutorials/junit/junit.html




http://pub.admc.com/howtos/junit4x/junit4x.html

http://junit.sourceforge.net/doc/cookbook/cookbook.htm

http://junit.org/junit/javadoc/4.5/

http://www.junit.org/

Documents

Junit Final