Java JUnit Tutorial - JUnit Features








JUnit test framework provides following important features

  • Fixtures

  • Test suites

  • Test runners

  • JUnit classes





Fixtures

Fixtures is a fixed state of a set of objects which can be used as a baseline for running tests.

A test fixture ensures that there is a fixed environment in which tests are run so that results are repeatable.

We can use the following two methods to setup a fixture.

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

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

Let's check one example:

import junit.framework.*;

public class JavaTest extends TestCase {
   protected int value1, value2;
   
   // assigning the values
   protected void setUp(){
      value1=1;
      value2=1;
   }

   // test method to add two values
   public void testAdd(){
      double result= value1 + value2;
      assertTrue(result == 2);
   }
}




Test suite

Test suite bundles unit tests cases and run it together.

In JUnit, both @RunWith and @Suite annotation are used to run the suite test.

Here is an example which 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
})
public class JunitTestSuite {
}

Here is the code for TestJunit1. 

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

public class TestJunit1 {

   
   @Test
   public void testPrintMessage() {  
      assertEquals(1, 1+1);     
   }
}

Here is the code for TestJunit2. 

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

public class TestJunit2 {

   @Test
   public void testSalutationMessage() {
     assertEquals(1, 1+0);     
   }
}

Test runner

Test runner can execute the test cases. 

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

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