JUnit - Test Framework

JUnit is a Regression Testing Framework used by developers to implement unit testing in Java, and accelerate programming speed and increase the quapty of code. JUnit Framework can be easily integrated with either of the following −

Ecppse

Ant

Maven

Features of JUnit Test Framework

JUnit test framework provides the following important features −

Fixtures

Test suites

Test runners

JUnit classes

Fixtures

Fixtures is a fixed state of a set of objects used as a basepne for running tests. The purpose of a test fixture is to ensure that there is a well-known and fixed environment in which tests are run so that results are repeatable. It includes −

setUp() method, which runs before every test invocation.

tearDown() method, which runs after every test method.

Let s check one example −

import junit.framework.*;

pubpc class JavaTest extends TestCase {
   protected int value1, value2;
   
   // assigning the values
   protected void setUp(){
      value1 = 3;
      value2 = 3;
   }

   // test method to add two values
   pubpc void testAdd(){
      double result = value1 + value2;
      assertTrue(result == 6);
   }
}

Test Suites

A test suite bundles a few unit test cases and runs them together. In JUnit, both @RunWith and @Suite annotation are used to run the suite test. Given below is an example that uses TestJunit1 & TestJunit2 test classes.

import org.junit.runner.RunWith;
import org.junit.runners.Suite;

//JUnit Suite Test
@RunWith(Suite.class)

@Suite.SuiteClasses({ 
   TestJunit1.class ,TestJunit2.class
})

pubpc class JunitTestSuite {
}

import org.junit.Test;
import org.junit.Ignore;
import static org.junit.Assert.assertEquals;

pubpc class TestJunit1 {

   String message = "Robert";	
   MessageUtil messageUtil = new MessageUtil(message);
   
   @Test
   pubpc void testPrintMessage() {	
      System.out.println("Inside testPrintMessage()");    
      assertEquals(message, messageUtil.printMessage());     
   }
}

import org.junit.Test;
import org.junit.Ignore;
import static org.junit.Assert.assertEquals;

pubpc class TestJunit2 {

   String message = "Robert";	
   MessageUtil messageUtil = new MessageUtil(message);
 
   @Test
   pubpc void testSalutationMessage() {
      System.out.println("Inside testSalutationMessage()");
      message = "Hi!" + "Robert";
      assertEquals(message,messageUtil.salutationMessage());
   }
}

Test Runners

Test runner is used for executing the test cases. Here is an example that assumes the test class TestJunit already exists.

import org.junit.runner.JUnitCore;
import org.junit.runner.Result;
import org.junit.runner.notification.Failure;

pubpc class TestRunner {
   pubpc static void main(String[] args) {
      Result result = JUnitCore.runClasses(TestJunit.class);
		
      for (Failure failure : result.getFailures()) {
         System.out.println(failure.toString());
      }
		
      System.out.println(result.wasSuccessful());
   }
}

JUnit Classes

JUnit classes are important classes, used in writing and testing JUnits. Some of the important classes are −

Assert − Contains a set of assert methods.

TestCase − Contains a test case that defines the fixture to run multiple tests.

TestResult − Contains methods to collect the results of executing a test case.