JUnit - Extensions

JWebUnit

JWebUnit is one of the Extensions for testing in Java. It is used to test Web applications. It checks the accuracy of a web application by wrapping up frameworks like HtmlUnit and Selenium with a simple testing interface.

JWebUnit provides a very accurate Java API that can navigate web applications. JWebUnit includes a lot of web application features such as,

• Navigation Links
• Form Entry and Submission
• Validation of table contents
• And Many other business web applications

In JWebUnit testing, there is no need to rewrite the tests if one wants to switch from HtmlUnit to any other Java plugins such as Selenium.

Let us look at an example of JWebUnit.

import junit.framework.TestCase;
import net.sourceforge.jwebunit.WebTester;

public class JWebUnitExample extends TestCase {
   private WebTester tester;
   
   public JWebUnitExample(String name) {
      super(name);
      tester = new WebTester();
   }
   
   public void setUp() throws Exception {
      getTestContext().setBaseUrl("http://myserver:3000/testApp");
   }
   
   @Test
   public void testPage() {
      beginAt("/info.html");
   }
}

You can also try this code with Online Java Compiler

Run Code

XMLUnit

XMLUnit is yet another essential extension of the Java Testing Units. It provides the developer with a set of supporting classes that are used to make assertions for the following,

• The differences between two XML pieces (via Diff and DetailedDiff classes).
• The validity of a part of XML (via Validator class).
• The outcome of transforming a bit of XML using XSLT (via Transform class).
• The evaluation of an XPath expression on the part of XML (via classes implementing the XpathEngine interface).
• Individual nodes in a piece of XML are exposed by DOM Traversal (via NodeTest class).

Let us look at a very basic code of XMLUnit to assert two pieces of XML code are equal.

import org.custommonkey.xmlunit.XMLTestCase;

public class XmlExample extends XMLTestCase {
   // this test method compare two pieces of the XML
   @Test
   public void testXmlEqual() throws Exception {
      String myXML_1 = "<msg><uuid>0x00435A8C</uuid></msg>";
      String myXML_2 = "<msg><localId>1234</localId></msg>";
      assertXMLEqual("Comparing myXML_1 with myXML_2", myXML_1, myXML_2);
   }
}

You can also try this code with Online Java Compiler

Run Code

MockObject

Mock Objects simulate the characteristics of complex and natural non-mock objects. They are helpful when a real object is impractical or impossible to incorporate into a unit test.

The typical coding style for testing with mock objects is,

• Create instances of mock objects.
• Set state and expectations in the mock objects.
• Invoke domain code with mock objects as parameters.
• Verify consistency in the mock objects.

Below is a classic example of Mock Objects.

import org.jmock.Mockery;
import org.jmock.Expectations;


class MockObjectExample extends TestCase {
   Mockery context = new Mockery();
   public void setMessage() {
      final Sub sub = context.mock(Sub.class);


      Pub pub = new Pub();
      pub.add(sub);
    
      final String message = "some random text";
      
      // expectations
      context.checking(new Expectations() {
         oneOf (sub).receive(message);
      });


      // execute
      pub.publish(message);
      
      // verify
      context.assertIsSatisfied();
   }
}

You can also try this code with Online Java Compiler

Run Code

FAQs

1. What is JUnit? 
   JUnit is a framework in Java used for unit testing. It is vital in the development of test-driven development. It is part of the xUnit frameworks. We link the JUnit as a JAR file at compile time. JUnit5 resides under the org.junit.jupiter package in Java.
    
2. What are the major extensions present in JUnit? 
   There are four basic extensions present in JUnit, each performing a specific task,
   Cactus
   JWebUnit
   XMLUnit
   Mock Objects
    
3. What is the latest version of JUnit? 
   The most recent version of JUnit is Junit5, although the previous versions of Junit are still equally famous. For instance, JUnit4 has over 100,000 usages.
    
4. What is the significance JWebUnit? 
   JWebUnit is one of the Extensions for testing in Java. It is used to test Web applications. It checks the accuracy of a web application by wrapping up frameworks like HtmlUnit and Selenium with a simple testing interface.
    
5. What is the significance of XMLUnit? 
   XMLUnit is yet another essential extension of the Java Testing Units. It provides the developer with supporting classes used to make crucial assertions in testing.

Key Takeaways

This Blog covered all the necessary points about JUnit and all the extensions present in JUnit. We further discussed how to implement JUnit testing in Java. 
Don’t stop here; check out Coding Ninjas for more unique courses and guided paths. Also, try Coding Ninjas Studio for more exciting articles, interview experiences, and fantastic Data Structures and Algorithms problems.