Test - Junit Basic

Test - Junit Basic

Definition

Testing, Unit Testing, Junit Testing

Testing is the process of checking the functionality of the application whether it is working as per requirements.
Unit testing is the testing of single entity (class or method).
JUnit is a unit testing framework for the Java Programming Language.

Junit Features

open source framework
use annoation to identify test methods
provide assertion for testing expected results
provide test runners for running tests

Basic Usage

STEP 1: Create a Class to test

public class MessageUtil {...}

STEP 2: Create Test Case Class

import org.junit.Test;
import static org.junit.Assert.assertEquals;
public class TestJunit {
   String message = "Hello World";
   MessageUtil messageUtil = new MessageUtil(message);

   @Test
   public void testPrintMessage() {
      assertEquals(message,messageUtil.printMessage());
   }
}

STEP 3: Create Test Runner Class (Optional with Eclipse)

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

public class TestRunner {
   public 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());
   }
}

Note: Most IDE integrates with Junit so that you don’t need to write the Test Runner by yourself. It’s already handled by the platform. Just a click of button triggers the process in the backend.

Types of Conditions

Assertion Test

This class provides a set of assertion methods useful for writing tests.

void assertEquals(boolean expected, boolean actual)
void assertFalse(boolean condition)
void assertTrue(boolean condition)
void assertNull(Object object)
void assertNotNull(Object object)
void fail()

import org.junit.Test;
import static org.junit.Assert.*;
public class TestJunit1 {
   @Test
   public void testAdd() {
      //test data
      int num= 5;
      String temp= null;
      String str= "Junit is working fine";

      //check for equality
      assertEquals("Junit is working fine", str);

      //check for false condition
      assertFalse(num > 6);

      //check for not null value
      assertNotNull(str);
   }
}

Time Test

@Test(timeout=1000)

Exception Test

@Test(expected = XXXException.class)

Annotation

@Test run the method as a test case
@Before run the method before each test
@After run the method after each test
@BeforeClass run once before any methods in the class
@AfterClass run once after all tests have finished
@Ignore ignore the test

JMock

Mock objects help you design and test the relations between the objects entangling the whole system.

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

public class PublisherTest extends TestCase {
    Mockery context = new Mockery();

    public void testOneSubscriberReceivesAMessage() {
        // set up
        final Subscriber subscriber = context.mock(Subscriber.class);

        Publisher publisher = new Publisher();
        publisher.add(subscriber);

        final String message = "message";

        // expectations
        context.checking(new Expectations() {
            oneOf (subscriber).receive(message);
        });

        // execute
        publisher.publish(message);

        // verify
        context.assertIsSatisfied();
    }
}

More info about Mock Test can be found here: 用JUnit写Unit Test和Integration Test