JUnit 4 Vs TestNG – Comparison

JUnit 4 and TestNG are both very popular unit test framework in Java. Both frameworks look very similar in functionality. Which one is better? Which unit test framework should I use in Java project?

Here I did a feature comparison between JUnit 4 and TestNG.

junit-vs-testngjpg

1. Annotation Support

The annotation supports are implemented in both JUnit 4 and TestNG look similar.

FeatureJUnit 4TestNG
test annotation@Test@Test
run before all tests in this suite have run@BeforeSuite
run after all tests in this suite have run@AfterSuite
run before the test@BeforeTest
run after the test@AfterTest
run before the first test method that belongs to any of these groups is invoked@BeforeGroups
run after the last test method that belongs to any of these groups is invoked@AfterGroups
run before the first test method in the current class is invoked@BeforeClass@BeforeClass
run after all the test methods in the current class have been run@AfterClass@AfterClass
run before each test method@Before@BeforeMethod
run after each test method@After@AfterMethod
ignore test@ignore@Test(enbale=false)
expected exception@Test(expected = ArithmeticException.class)@Test(expectedExceptions = ArithmeticException.class)
timeout@Test(timeout = 1000)@Test(timeout = 1000)

The main annotation differences between JUnit4 and TestNG are

1. In JUnit 4, we have to declare “@BeforeClass” and “@AfterClass” method as static method. TestNG is more flexible in method declaration, it does not have this constraints.

2. 3 additional setUp/tearDown level: suite and group (@Before/AfterSuite, @Before/AfterTest, @Before/AfterGroup). See more detail here.

JUnit 4

    @BeforeClass
    public static void oneTimeSetUp() {
        // one-time initialization code   
    	System.out.println("@BeforeClass - oneTimeSetUp");
    }

TestNG

    @BeforeClass
    public void oneTimeSetUp() {
        // one-time initialization code   
    	System.out.println("@BeforeClass - oneTimeSetUp");
}

In JUnit 4, the annotation naming convention is a bit confusing, e.g “Before”, “After” and “Expected”, we do not really understand what is “Before” and “After” do, and what we “Expected” from test method? TestiNG is easier to understand, it uses “BeforeMethod”, “AfterMethod” and “ExpectedException” instead.

2. Exception Test

The “exception testing” means what exception throws from the unit test, this feature is implemented in both JUnit 4 and TestNG.

JUnit 4

      @Test(expected = ArithmeticException.class)  
	public void divisionWithException() {  
	  int i = 1/0;
	}

TestNG

      @Test(expectedExceptions = ArithmeticException.class)  
	public void divisionWithException() {  
	  int i = 1/0;
	}

3. Ignore Test

The “Ignored” means whether it should ignore the unit test, this feature is implemented in both JUnit 4 and TestNG .

JUnit 4

        @Ignore("Not Ready to Run")  
	@Test
	public void divisionWithException() {  
	  System.out.println("Method is not ready yet");
	}

TestNG

	@Test(enabled=false)
	public void divisionWithException() {  
	  System.out.println("Method is not ready yet");
	}

4. Time Test

The “Time Test” means if an unit test takes longer than the specified number of milliseconds to run, the test will terminated and mark as fails, this feature is implemented in both JUnit 4 and TestNG .

JUnit 4

        @Test(timeout = 1000)  
	public void infinity() {  
		while (true);  
	}

TestNG

	@Test(timeOut = 1000)  
	public void infinity() {  
		while (true);  
	}

5. Suite Test

The “Suite Test” means bundle a few unit test and run it together. This feature is implemented in both JUnit 4 and TestNG. However both are using very different method to implement it.

JUnit 4

The “@RunWith” and “@Suite” are use to run the suite test. The below class means both unit test “JunitTest1” and “JunitTest2” run together after JunitTest5 executed. All the declaration is define inside the class.

@RunWith(Suite.class)
@Suite.SuiteClasses({
        JunitTest1.class,
        JunitTest2.class
})
public class JunitTest5 {
}

TestNG

XML file is use to run the suite test. The below XML file means both unit test “TestNGTest1” and “TestNGTest2” will run it together.

<!DOCTYPE suite SYSTEM "http://beust.com/testng/testng-1.0.dtd" >
<suite name="My test suite">
  <test name="testing">
    <classes>
       <class name="com.fsecure.demo.testng.TestNGTest1" />
       <class name="com.fsecure.demo.testng.TestNGTest2" />
    </classes>
  </test>
</suite>

TestNG can do more than bundle class testing, it can bundle method testing as well. With TestNG unique “Grouping” concept, every method is tie to a group, it can categorize tests according to features. For example,

Here is a class with four methods, three groups (method1, method2 and method3)

        @Test(groups="method1")
	public void testingMethod1() {  
	  System.out.println("Method - testingMethod1()");
	}  
 
	@Test(groups="method2")
	public void testingMethod2() {  
		System.out.println("Method - testingMethod2()");
	}  
 
	@Test(groups="method1")
	public void testingMethod1_1() {  
		System.out.println("Method - testingMethod1_1()");
	}  
 
	@Test(groups="method4")
	public void testingMethod4() {  
		System.out.println("Method - testingMethod4()");
	}

With the following XML file, we can execute the unit test with group “method1” only.

<!DOCTYPE suite SYSTEM "http://beust.com/testng/testng-1.0.dtd" >
<suite name="My test suite">
  <test name="testing">
  	<groups>
      <run>
        <include name="method1"/>
      </run>
    </groups>
    <classes>
       <class name="com.fsecure.demo.testng.TestNGTest5_2_0" />
    </classes>
  </test>
</suite>

With “Grouping” test concept, the integration test possibility is unlimited. For example, we can only test the “DatabaseFuntion” group from all of the unit test classes.

6. Parameterized Test

The “Parameterized Test” means vary parameter value for unit test. This feature is implemented in both JUnit 4 and TestNG. However both are using very different method to implement it.

JUnit 4

The “@RunWith” and “@Parameter” is use to provide parameter value for unit test, @Parameters have to return List[], and the parameter will pass into class constructor as argument.

@RunWith(value = Parameterized.class)
public class JunitTest6 {
 
	 private int number;
 
	 public JunitTest6(int number) {
	    this.number = number;
	 }
 
	 @Parameters
	 public static Collection<Object[]> data() {
	   Object[][] data = new Object[][] { { 1 }, { 2 }, { 3 }, { 4 } };
	   return Arrays.asList(data);
	 }
 
	 @Test
	 public void pushTest() {
	   System.out.println("Parameterized Number is : " + number);
	 }
}

It has many limitations here; we have to follow the “JUnit” way to declare the parameter, and the parameter has to pass into constructor in order to initialize the class member as parameter value for testing. The return type of parameter class is “List []”, data has been limited to String or a primitive value for testing.

TestNG

XML file or “@DataProvider” is use to provide vary parameter for testing.

XML file for parameterized test.
Only “@Parameters” declares in method which needs parameter for testing, the parametric data will provide in TestNG’s XML configuration files. By doing this, we can reuse a single test case with different data sets and even get different results. In addition, even end user, QA or QE can provide their own data in XML file for testing.

Unit Test

      public class TestNGTest6_1_0 {
 
	   @Test
	   @Parameters(value="number")
	   public void parameterIntTest(int number) {
	      System.out.println("Parameterized Number is : " + number);
	   }
 
      }

XML File

<!DOCTYPE suite SYSTEM "http://beust.com/testng/testng-1.0.dtd" >
<suite name="My test suite">
  <test name="testing">
 
    <parameter name="number" value="2"/> 	
 
    <classes>
       <class name="com.fsecure.demo.testng.TestNGTest6_0" />
    </classes>
  </test>
</suite>

@DataProvider for parameterized test.

While pulling data values into an XML file can be quite handy, tests occasionally require complex types, which can’t be represented as a String or a primitive value. TestNG handles this scenario with its @DataProvider annotation, which facilitates the mapping of complex parameter types to a test method.

@DataProvider for Vector, String or Integer as parameter

        @Test(dataProvider = "Data-Provider-Function")
	public void parameterIntTest(Class clzz, String[] number) {
	   System.out.println("Parameterized Number is : " + number[0]);
	   System.out.println("Parameterized Number is : " + number[1]);
	}
 
	//This function will provide the patameter data
	@DataProvider(name = "Data-Provider-Function")
	public Object[][] parameterIntTestProvider() {
		return new Object[][]{
				   {Vector.class, new String[] {"java.util.AbstractList", 
"java.util.AbstractCollection"}},
				   {String.class, new String[] {"1", "2"}},
				   {Integer.class, new String[] {"1", "2"}}
				  };
	}

@DataProvider for object as parameter
P.S “TestNGTest6_3_0” is an simple object with just get set method for demo.

        @Test(dataProvider = "Data-Provider-Function")
	public void parameterIntTest(TestNGTest6_3_0 clzz) {
	   System.out.println("Parameterized Number is : " + clzz.getMsg());
	   System.out.println("Parameterized Number is : " + clzz.getNumber());
	}
 
	//This function will provide the patameter data
	@DataProvider(name = "Data-Provider-Function")
	public Object[][] parameterIntTestProvider() {
 
		TestNGTest6_3_0 obj = new TestNGTest6_3_0();
		obj.setMsg("Hello");
		obj.setNumber(123);
 
		return new Object[][]{
				   {obj}
		};
	}

TestNG’s parameterized test is very user friendly and flexible (either in XML file or inside the class). It can support many complex data type as parameter value and the possibility is unlimited. As example above, we even can pass in our own object (TestNGTest6_3_0) for parameterized test

7. Dependency Test

The “Parameterized Test” means methods are test base on dependency, which will execute before a desired method. If the dependent method fails, then all subsequent tests will be skipped, not marked as failed.

JUnit 4

JUnit framework is focus on test isolation; it did not support this feature at the moment.

TestNG

It use “dependOnMethods “ to implement the dependency testing as following

        @Test
	public void method1() {
	   System.out.println("This is method 1");
	}
 
	@Test(dependsOnMethods={"method1"})
	public void method2() {
		System.out.println("This is method 2");
	}

The “method2()” will execute only if “method1()” is run successfully, else “method2()” will skip the test.

Conclusion

After go thought all the features comparison, i suggest to use TestNG as core unit test framework for Java project, because TestNG is more advance in parameterize testing, dependency testing and suite testing (Grouping concept). TestNG is meant for high-level testing and complex integration test. Its flexibility is especially useful with large test suites. In addition, TestNG also cover the entire core JUnit4 functionality. It’s just no reason for me to use JUnit anymore.

References

TestNG
————
http://en.wikipedia.org/wiki/TestNG
http://www.ibm.com/developerworks/java/library/j-testng/
http://testng.org/doc/index.html
http://beust.com/weblog/

JUnit
———–
http://en.wikipedia.org/wiki/JUnit
http://www.ibm.com/developerworks/java/library/j-junit4.html
http://junit.sourceforge.net/doc/faq/faq.htm
http://www.devx.com/Java/Article/31983/0/page/3
http://ourcraft.wordpress.com/2008/08/27/writing-a-parameterized-junit-test/

TestNG VS JUnit
——————
http://docs.codehaus.org/display/XPR/Migration+to+JUnit4+or+TestNG
http://www.ibm.com/developerworks/java/library/j-cq08296/index.html
http://www.cavdar.net/2008/07/21/junit-4-in-60-seconds/

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About the Author

mkyong
Founder of Mkyong.com and HostingCompass.com, love Java and open source stuff. Follow him on Twitter, or befriend him on Facebook or Google Plus. If you like my tutorials, consider make a donation to these charities.

Comments

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  • Kannan

    Good and Simple article ! Could you also please provide a comparison on the reporting abilities and formats between junit4 and testng ?

  • Atish

    Very useful. Short and sweet!

  • Agen Wei

    Below are a few features of JUnit that more or less cope with the shortfalls mentioned for Junit,
    1, Categories:
    provide similar “grouping” feature as that of TestNG
    https://github.com/junit-team/junit/wiki/Categories

    2, As i read from this article, JUnit seems to support Parameterized-tests with objects,
    http://java-open-source.com/stream/13f3326236e/simple-junit4-and-parameterized-test-example

    and JUnit has another killer feature, Theories:
    https://github.com/junit-team/junit/wiki/Theories
    by taking advantage of this feature, you could specify a range of values for the input parameters of your unit test methods, and JUnit would then automatically combine them all together randomly to verify you tests.

    3,Assumptions of Junit, could help save the credit back a little for itself for missing the “Dependency test” feature,
    https://github.com/junit-team/junit/wiki/Assumptions-with-assume

  • agen

    It kinda extracts the complexity of rich features into a bunch of xml settings, and I don’t like it very much that way.

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  • prasanth

    Hi friends,
    Am running a tests in suite consider IRCTC website
    eg:suite1.class contains 3class files
    1.login.class-contains info for logging in
    2.Search schedule-contains info for searching schedules
    3.Booking tickets-if both test are pass it should execute third class file, else it should fail and skip the other test cases
    My query is how to use dependency in TestNG for each and every class file???thanks in advance for ur valuable response….)waiting for ur answers…)

  • Taoufik Mohdit

    Very useful article! One thing worth mentioning though, Junit as well supports what is called in the article “Grouping concept” by using @Category, @IncludeCategory and @ExcludeCategory annotations (an example can be found here: https://github.com/junit-team/junit/wiki/Categories)

  • Manpreet

    TestNG supports parallel execution which I would say is one of the coolest feature.

    where parallel can be either of – classes/tests/methods

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  • Venky

    Simple and straight forward explanation.Thanks for sharing it.

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  • Srichandar

    Thank you so much for the awesome explanation !!

  • Ankur

    Great comparison…. thanks for extending your knowledge

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  • Piotr Zawadzki

    Grouping is now available in JUnit 4.8+
    It’s described here: http://maven.apache.org/surefire/maven-surefire-plugin/examples/junit.html under ‘Using JUnit Categories’

  • Sateesh

    It is very much helpful.

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  • redsam

    you actually missed the junit killer feature : Rules !

    i would use test ng and agree your conclusion when testng would provide a similar concept. especially when you work on many projects and want to share test glue/base code Rulse are awsome. they allow to delegate logic instead of inheritence.

    • RainerW

      Yep would agree. I was on the way to switch to TestNG, when JUnit introduced Rules. It’s basically a Strategy pattern for Before/After code.

      I would also normally use ExpectedException:

      @Rule public ExpectedException exception = ExpectedException.none();
       
      @Test
      public void divisionWithException() 
      {  
         // Your TestNG and JUnit sample would not detect that the exception was actually thrown in the 'prepare/setup' code 
        int s = 1/0;  
       
        // verify
        exception.expect(ArithmeticException.class);
       
        // execute, this is the exception we expect
        int i = s/0;
      }
  • Anand

    Great explanation..thank you..

  • abhishek

    Can we run junit class withn testNG configuration

    Hi Guys i am facing weired problem.

    1.Have one Junit class which is running fine.
    2.Have configured the testng class as well.
    3.Copied junitlibrary as well.

    But still testNG is not showing me the result

    Can any one please help me with that.
    Any help will be appreciated

  • fan

    It has been a while that I use the tutorials on your website.
    Just want you to know that I love it!
    Greate, straight, and simple explanation of everything…

  • Ganesh

    It is very good and easily undastandable

    • Ganesh

      thank Q

  • Mayuresh

    Wonderful article. And the fact that Cedric himself added this article in official testNG docs shows how thoroughly written it was!
    Although I was always pro testNG for overall automation (and I am not just talking about unit testing here), this article only helped in confirming my decision

  • Shobana

    very helpful content

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  • Adam

    TestNG is supposed to make things easier but it adds a bunch of XML… in my experience, XML never makes things simpler. Looks to me like all TestNG does is take the complexity and put it somewhere else, giving the illusion of simpler code.

    • Carlos

      Totally agree. Although TestNG has a few extra features that seem very nice at first, it adds some complexity in XML configurations, which is very annoying to maintain. When I think about having to configure my tests using XML files, I realize that all those nice features aren’t really necessary for any project I’ve ever worked with. Also, JUnit has officially releases @Rule, which will cover other problems of the framework compared to TestNG, like parallel testing.

  • pothuganti nabee

    Really its very usefull info…thanks dude..

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  • raghuramreddy p

    Very helpful

  • Anand

    I read most of your post..

    Man you are doing great job, keep adding more and more helpful post.

  • Vaitheesh

    Very helpful… Thanks a lot..

  • http://serrano.tk Michaelangelo

    Thanks for this helpful aricle. i used this as reference for BSCS students

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  • Joe Mama

    You missed the most significant comparison, which is around the execution model–JUnit creates a separate instance for each unit test run, and TestNG does not.

    • http://www.mkyong.com mkyong

      Thanks for the addition, would you mind to show some examples to demonstrate about it?

  • http://www.eonblast.com Henning

    Very helpful, thanks a lot.

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  • http://blog.eliotpearson.com Eliot

    Thanks for the post. Someone recently asked me about TestNG. I have used JUnit for years, and I do see some of the shortfalls TestNG fixes. I now have a real good idea about some of the differences.

  • Yogendra

    This is perfect information.

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  • Jake

    Um, you ripped off this paragraph directly from the IBM article:

    TestNG’s trick of skipping, rather than failing, can really take the pressure off in large test suites. Rather than trying to figure out why 50 percent of the test suite failed, your team can concentrate on why 50 percent of it was skipped! Better yet, TestNG complements its dependency testing setup with a mechanism for rerunning only failed tests.

    • mkyong

      Ya, i found this paragraph is quite descriptive, may be i should not did it, article updated. Thank~

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  • Vijayan Srinivasan

    Good Post!

  • Cedric

    Thanks for the detailed comparison, I added a link to this article in the TestNG documentation: http://testng.org/doc/misc.html

    • mkyong

      Thanks for added this article in official TestNG documentation, good to know this is helpful