JUnit Quick Guide

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Testing is the process of checking the functionality of the application whether it is working as per requirements and to ensure that at developer level, unit testing comes into picture.

Unit testing is the testing of single entity (class or method). Unit testing is very essential to every software company to give a quality product to their customers.

Unit testing can be done in two ways

Manual testingAutomated testing

Executing the test cases manually without any tool support is known as manual testing.

  • Time consuming and tedious: Since test cases are executed by human resources so it is very slow and tedious.

  • Huge investment in human resources: As test cases need to be executed manually so more testers are required in manual testing.

  • Less reliable: Manual testing is less reliable as tests may not be performed with precision each time because of human errors.

  • Non-programmable: No programming can be done to write sophisticated tests which fetch hidden information.

Taking tool support and executing the test cases by using automation tool is known as automation testing.

  • Fast Automation runs test cases significantly faster than human resources.

  • Less investment in human resources:Test cases are executed by using automation tool so less tester are required in automation testing.

  • More reliable: Automation tests perform precisely same operation each time they are run.

  • Programmable: Testers can program sophisticated tests to bring out hidden information.

What is JUnit ?

JUnit is a unit testing framework for the Java Programming Language. It is important in the test driven development, and is one of a family of unit testing frameworks collectively known as xUnit.

JUnit promotes the idea of "first testing then coding", which emphasis on setting up the test data for a piece of code which can be tested first and then can be implemented . This approach is like "test a little, code a little, test a little, code a little..." which increases programmer productivity and stability of program code that reduces programmer stress and the time spent on debugging.

Features

  • JUnit is an open source framework which is used for writing & running tests.

  • Provides Annotation to identify the test methods.

  • Provides Assertions for testing expected results.

  • Provides Test runners for running tests.

  • JUnit tests allow you to write code faster which increasing quality

  • JUnit is elegantly simple. It is less complex & takes less time.

  • JUnit tests can be run automatically and they check their own results and provide immediate feedback. There's no need to manually comb through a report of test results.

  • JUnit tests can be organized into test suites containing test cases and even other test suites.

  • Junit shows test progress in a bar that is green if test is going fine and it turns red when a test fails.

What is a Unit Test Case ?

A Unit Test Case is a part of code which ensures that the another part of code (method) works as expected. To achieve those desired results quickly, test framework is required .JUnit is perfect unit test framework for java programming language.

A formal written test-case is characterized by a known input and by an expected output, which is worked out before the test is executed. The known input should test a precondition and the expected output should test a postcondition.

There must be at least two test cases for each requirement: one positive test and one negative test. If a requirement has sub-requirements, each sub-requirement must have at least two test cases as positive and negative.

JUnit - Environment Setup

JUnit is a framework for Java, so the very first requirement is to have JDK installed in your machine.

System Requirement

JDK1.5 or above.
Memoryno minimum requirement.
Disk Spaceno minimum requirement.
Operating Systemno minimum requirement.

Step 1 - verify Java installation in your machine

Now open console and execute the following java command.

OSTaskCommand
WindowsOpen Command Consolec:\> java -version
LinuxOpen Command Terminal$ java -version
MacOpen Terminalmachine:~ joseph$ java -version

Let's verify the output for all the operating systems:

OSOutput
Windows java version "1.6.0_21"
Java(TM) SE Runtime Environment (build 1.6.0_21-b07)
Java HotSpot(TM) Client VM (build 17.0-b17, mixed mode, sharing)
Linux java version "1.6.0_21"
Java(TM) SE Runtime Environment (build 1.6.0_21-b07)
Java HotSpot(TM) Client VM (build 17.0-b17, mixed mode, sharing)
Mac java version "1.6.0_21"
Java(TM) SE Runtime Environment (build 1.6.0_21-b07)
Java HotSpot(TM)64-Bit Server VM (build 17.0-b17, mixed mode, sharing)

If you do not have Java installed, install the Java Software Development Kit (SDK) from http://www.oracle.com/technetwork/java/javase/downloads/index.html. We are assuming Java 1.6.0_21 as installed version for this tutorial.

Step 2: Set JAVA environment

Set the JAVA_HOME environment variable to point to the base directory location where Java is installed on your machine. For example

OSOutput
WindowsSet the environment variable JAVA_HOME to C:\Program Files\Java\jdk1.6.0_21
Linuxexport JAVA_HOME=/usr/local/java-current
Macexport JAVA_HOME=/Library/Java/Home

Append Java compiler location to System Path.

OSOutput
WindowsAppend the string ;C:\Program Files\Java\jdk1.6.0_21\bin to the end of the system variable, Path.
Linuxexport PATH=$PATH:$JAVA_HOME/bin/
Macnot required

Verify Java Installation using java -version command explained above.

Step 3: Download Junit archive

Download latest version of JUnit jar file from http://www.junit.org. At the time of writing this tutorial, I downloaded Junit-4.10.jar and copied it into C:\>JUnit folder.

OSArchive name
Windowsjunit4.10.jar
Linuxjunit4.10.jar
Macjunit4.10.jar

Step 4: Set JUnit environment

Set the JUNIT_HOME environment variable to point to the base directory location where JUNIT jar is stored on your machine. Assuming, we've stored junit4.10.jar in JUNIT folder on various Operating Systems as follows.

OSOutput
WindowsSet the environment variable JUNIT_HOME to C:\JUNIT
Linuxexport JUNIT_HOME=/usr/local/JUNIT
Macexport JUNIT_HOME=/Library/JUNIT

Step 5: Set CLASSPATH variable

Set the CLASSPATH environment variable to point to the JUNIT jar location. Assuming, we've stored junit4.10.jar in JUNIT folder on various Operating Systems as follows.

OSOutput
WindowsSet the environment variable CLASSPATH to %CLASSPATH%;%JUNIT_HOME%\junit4.10.jar;.;
Linuxexport CLASSPATH=$CLASSPATH:$JUNIT_HOME/junit4.10.jar:.
Macexport CLASSPATH=$CLASSPATH:$JUNIT_HOME/junit4.10.jar:.

Step 6: Test JUnit Setup

Create a java class file name TestJunit in C:\ > JUNIT_WORKSPACE

   
import org.junit.Test;
import static org.junit.Assert.assertEquals;
public class TestJunit {
   @Test
   public void testAdd() {
      String str= "Junit is working fine";
      assertEquals("Junit is working fine",str);
   }
}

Create a java class file name TestRunner in C:\ > JUNIT_WORKSPACE to execute Test case(s)

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());
   }
}  	

Step 7: Verify the Result

Compile the classes using javac compiler as follows

C:\JUNIT_WORKSPACE>javac TestJunit.java TestRunner.java

Now run the Test Runner to see the result

C:\JUNIT_WORKSPACE>java TestRunner

Verify the output.

true

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 quality of code. JUnit Framework can be easily integrated with either of the followings:

  • Eclipse

  • Ant

  • Maven

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 used as a baseline 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.*;

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

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

Test suite

Test suite means bundle a few unit test 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 {
}
import org.junit.Test;
import org.junit.Ignore;
import static org.junit.Assert.assertEquals;

public class TestJunit1 {

   String message = "Robert";	
   MessageUtil messageUtil = new MessageUtil(message);
   
   @Test
   public 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;

public class TestJunit2 {

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

Test runner

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

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());
   }
}

JUnit classes

JUnit classes are important classes which is used in writing and testing JUnits. Some of the important classes are

  • Assert which contain a set of assert methods.

  • TestCase which contain a test case defines the fixture to run multiple tests.

  • TestResult which contain methods to collect the results of executing a test case.

JUnit Basic Usage

Now we'll show you a step by step process to get a kick start in Junit using a basic example.

Create a Class

  • Create a java class to be tested say MessageUtil.java in C:\ > JUNIT_WORKSPACE

/*
* This class prints the given message on console.
*/
public class MessageUtil {

   private String message;

   //Constructor
   //@param message to be printed
   public MessageUtil(String message){
      this.message = message;
   }
      
   // prints the message
   public String printMessage(){
      System.out.println(message);
      return message;
   }   
}  

Create Test Case Class

  • Create a java test class say TestJunit.java.

  • Add a test method testPrintMessage() to your test class.

  • Add an Annotaion @Test to method testPrintMessage().

  • Implement the test condition and check the condition using assertEquals API of Junit.

Create a java class file name TestJunit.java in C:\ > JUNIT_WORKSPACE

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());
   }
}

Create Test Runner Class

  • Create a TestRunner java class.

  • Use runClasses method of JUnitCore class of JUnit to run test case of above created test class

  • Get the result of test cases run in Result Object

  • Get failure(s) using getFailures() methods of Result object

  • Get Success result using wasSuccessful() methods of Result object

Create a java class file name TestRunner.java in C:\ > JUNIT_WORKSPACE to execute Test case(s)

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());
   }
}  	

Compile the MessageUtil, Test case and Test Runner classes using javac

C:\JUNIT_WORKSPACE>javac MessageUtil TestJunit.java TestRunner.java

Now run the Test Runner which will run test case defined in provided Test Case class.

C:\JUNIT_WORKSPACE>java TestRunner

Verify the output.

Hello World
true

Now update TestJunit in C:\ > JUNIT_WORKSPACE so that test fails. Change the message string.

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() {
      message = "New Word";
      assertEquals(message,messageUtil.printMessage());
   }
}

Now run the Test Runner which will run test case defined in provided Test Case class.

C:\JUNIT_WORKSPACE>java TestRunner

Verify the output.

Hello World
testPrintMessage(TestJunit): expected:<[New Wor]d> but was:<[Hello Worl]d>
false

JUnit API

The most important package in JUnit is junit.framework which contain all the core classes. Some of the important class are

Serial NoClass NameFunctionality
1AssertA set of assert methods.
2TestCaseA test case defines the fixture to run multiple tests.
3TestResultA TestResult collects the results of executing a test case.
4TestSuiteA TestSuite is a Composite of Tests.

Assert Class

Following is the declaration for org.junit.Assert class:

public class Assert extends java.lang.Object

This class provides a set of assertion methods useful for writing tests. Only failed assertions are recorded. Some of the important methods of Assert class are:

S.N.Methods & Description
1void assertEquals(boolean expected, boolean actual)
Check that two primitives/Objects are equal
2void assertFalse(boolean condition)
Check that a condition is false
3void assertNotNull(Object object)
Check that an object isn't null.
4void assertNull(Object object)
Check that an object is null
5void assertTrue(boolean condition)
Check that a condition is true.
6void fail()
Fails a test with no message.

Let's try to cover few of the above mentioned methods in an example. Create a java class file name TestJunit1.java in C:\ > JUNIT_WORKSPACE

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);
   }
}

Next, let's create a java class file name TestRunner1.java in C:\ > JUNIT_WORKSPACE to execute Test case(s)

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

public class TestRunner1 {
   public static void main(String[] args) {
      Result result = JUnitCore.runClasses(TestJunit1.class);
      for (Failure failure : result.getFailures()) {
         System.out.println(failure.toString());
      }
      System.out.println(result.wasSuccessful());
   }
}  	

Compile the Test case and Test Runner classes using javac

C:\JUNIT_WORKSPACE>javac TestJunit1.java TestRunner1.java

Now run the Test Runner which will run test case defined in provided Test Case class.

C:\JUNIT_WORKSPACE>java TestRunner1

Verify the output.

true

TestCase Class

Following is the declaration for org.junit.TestCaset class:

public abstract class TestCase extends Assert implements Test

A test case defines the fixture to run multiple tests. Some of the important methods of TestCase class are

S.N.Methods & Description
1int countTestCases()
Counts the number of test cases executed by run(TestResult result).
2TestResult createResult()
Creates a default TestResult object.
3String getName()
Gets the name of a TestCase.
4TestResult run()
A convenience method to run this test, collecting the results with a default TestResult object.
5void run(TestResult result)
Runs the test case and collects the results in TestResult.
6void setName(String name)
Sets the name of a TestCase.
7void setUp()
Sets up the fixture, for example, open a network connection.
8void tearDown()
Tears down the fixture, for example, close a network connection.
9String toString()
Returns a string representation of the test case.

Let's try to cover few of the above mentioned methods in an example. Create a java class file name TestJunit2.java in C:\ > JUNIT_WORKSPACE

import junit.framework.TestCase;
import org.junit.Before;
import org.junit.Test;
public class TestJunit2 extends TestCase  {
   protected double fValue1;
   protected double fValue2;
   
   @Before 
   public void setUp() {
      fValue1= 2.0;
      fValue2= 3.0;
   }
	
   @Test
   public void testAdd() {
		
      //Count the number of test cases
	  System.out.println("No of Test Case = "+ this.countTestCases());
		
	 //test getName 
	 String name= this.getName();
	 System.out.println("Test Case Name = "+ name);

	 //test setName
	 this.setName("testNewAdd");
	 String newName= this.getName();
	 System.out.println("Updated Test Case Name = "+ newName);
   }
   //tearDown used to close the connection or clean up activities
   public void tearDown(  ) {
   }
}

Next, let's create a java class file name TestRunner2.java in C:\ > JUNIT_WORKSPACE to execute Test case(s)

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

public class TestRunner2 {
   public static void main(String[] args) {
      Result result = JUnitCore.runClasses(TestJunit2.class);
      for (Failure failure : result.getFailures()) {
         System.out.println(failure.toString());
      }
      System.out.println(result.wasSuccessful());
   }
} 

Compile the Test case and Test Runner classes using javac

C:\JUNIT_WORKSPACE>javac TestJunit2.java TestRunner2.java

Now run the Test Runner which will run test case defined in provided Test Case class.

C:\JUNIT_WORKSPACE>java TestRunner2

Verify the output.

No of Test Case = 1
Test Case Name = testAdd
Updated Test Case Name = testNewAdd
true

TestResult Class

Following is the declaration for org.junit.TestResult class:

public class TestResult extends Object

A TestResult collects the results of executing a test case. It is an instance of the Collecting Parameter pattern. The test framework distinguishes between failures and errors. A failure is anticipated and checked for with assertions. Errors are unanticipated problems like an ArrayIndexOutOfBoundsException. Some of the important methods of TestResult class are

S.N.Methods & Description
1void addError(Test test, Throwable t)
Adds an error to the list of errors.
2void addFailure(Test test, AssertionFailedError t)
Adds a failure to the list of failures.
3void endTest(Test test)
Informs the result that a test was completed.
4int errorCount()
Gets the number of detected errors.
5Enumeration<TestFailure> errors()
Returns an Enumeration for the errors.
6int failureCount()
Gets the number of detected failures.
7void run(TestCase test)
Runs a TestCase.
8int int runCount()
Gets the number of run tests.
9void startTest(Test test)
Informs the result that a test will be started.
10void stop()
Marks that the test run should stop.

Create a java class file name TestJunit3.java in C:\ > JUNIT_WORKSPACE

import org.junit.Test;
import junit.framework.AssertionFailedError;
import junit.framework.TestResult;

public class TestJunit3 extends TestResult {
   // add the error
   public synchronized void addError(Test test, Throwable t) {
      super.addError((junit.framework.Test) test, t);
   }

   // add the failure
   public synchronized void addFailure(Test test, AssertionFailedError t) {
      super.addFailure((junit.framework.Test) test, t);
   }
   @Test
   public void testAdd() {
   // add any test
   }
   
   // Marks that the test run should stop.
   public synchronized void stop() {
   //stop the test here
   }
}

Next, let's create a java class file name TestRunner3.java in C:\ > JUNIT_WORKSPACE to execute Test case(s)

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

public class TestRunner3 {
   public static void main(String[] args) {
      Result result = JUnitCore.runClasses(TestJunit3.class);
      for (Failure failure : result.getFailures()) {
         System.out.println(failure.toString());
      }
      System.out.println(result.wasSuccessful());
   }
}  	

Compile the Test case and Test Runner classes using javac

C:\JUNIT_WORKSPACE>javac TestJunit3.java TestRunner3.java

Now run the Test Runner which will run test case defined in provided Test Case class.

C:\JUNIT_WORKSPACE>java TestRunner3

Verify the output.

true

TestSuite Class

Following is the declaration for org.junit.TestSuite class:

public class TestSuite extends Object implements Test

A TestSuite is a Composite of Tests. It runs a collection of test cases. Some of the important methods of TestSuite class are

S.N.Methods & Description
1void addTest(Test test)
Adds a test to the suite.
2void addTestSuite(Class<? extends TestCase> testClass)
Adds the tests from the given class to the suite.
3int countTestCases()
Counts the number of test cases that will be run by this test.
4String getName()
Returns the name of the suite.
5void run(TestResult result)
Runs the tests and collects their result in a TestResult.
6void setName(String name)
Sets the name of the suite.
7Test testAt(int index)
Returns the test at the given index.
8int testCount()
Returns the number of tests in this suite.
9static Test warning(String message)
Returns a test which will fail and log a warning message.

Create a java class file name JunitTestSuite.java in C:\ > JUNIT_WORKSPACE to create Test suite

import junit.framework.*;
public class JunitTestSuite {
   public static void main(String[] a) {
      // add the test's in the suite
      TestSuite suite = new TestSuite(TestJunit1.class, 
      TestJunit2.class, TestJunit3.class );
      TestResult result = new TestResult();
      suite.run(result);
      System.out.println("Number of test cases = " + result.runCount());
    }
}

Compile the Test suite classes using javac

C:\JUNIT_WORKSPACE>javac JunitTestSuite.java 

Now run the Test Suite.

C:\JUNIT_WORKSPACE>java JunitTestSuite

Verify the output.

No of Test Case = 1
Test Case Name = testAdd
Updated Test Case Name = testNewAdd
Number of test cases = 3

JUnit - Writing Tests

Here we will see one complete example of JUnit testing using POJO class, Business logic class and a test class which will be run by test runner.

Create EmployeeDetails.java in C:\ > JUNIT_WORKSPACE which is a POJO class.

public class EmployeeDetails {

   private String name;
   private double monthlySalary;
   private int age;
   
   /**
   * @return the name
   */
   public String getName() {
      return name;
   }
   /**
   * @param name the name to set
   */
   public void setName(String name) {
      this.name = name;
   }
   /**
   * @return the monthlySalary
   */
   public double getMonthlySalary() {
      return monthlySalary;
   }
   /**
   * @param monthlySalary the monthlySalary to set
   */
   public void setMonthlySalary(double monthlySalary) {
      this.monthlySalary = monthlySalary;
   }
   /**
   * @return the age
   */
   public int getAge() {
      return age;
   }
   /**
   * @param age the age to set
   */
   public void setAge(int age) {
   this.age = age;
   }
}

EmployeeDetails class is used to

  • get/set the value of employee's name.

  • get/set the value of employee's monthly salary.

  • get/set the value of employee's age.

Create a EmpBusinessLogic.java in C:\ > JUNIT_WORKSPACE which contains business logic

public class EmpBusinessLogic {
   // Calculate the yearly salary of employee
   public double calculateYearlySalary(EmployeeDetails employeeDetails){
      double yearlySalary=0;
      yearlySalary = employeeDetails.getMonthlySalary() * 12;
      return yearlySalary;
   }
	
   // Calculate the appraisal amount of employee
   public double calculateAppraisal(EmployeeDetails employeeDetails){
      double appraisal=0;
      if(employeeDetails.getMonthlySalary() < 10000){
         appraisal = 500;
      }else{
         appraisal = 1000;
      }
      return appraisal;
   }
}

EmpBusinessLogic class is used for calculating

  • the yearly salary of employee.

  • the appraisal amount of employee.

Create a TestEmployeeDetails.java in C:\ > JUNIT_WORKSPACE which contains test cases to be tested

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

public class TestEmployeeDetails {
   EmpBusinessLogic empBusinessLogic =new EmpBusinessLogic();
   EmployeeDetails employee = new EmployeeDetails();

   //test to check appraisal
   @Test
   public void testCalculateAppriasal() {
      employee.setName("Rajeev");
      employee.setAge(25);
      employee.setMonthlySalary(8000);
      double appraisal= empBusinessLogic.calculateAppraisal(employee);
      assertEquals(500, appraisal, 0.0);
   }

   // test to check yearly salary
   @Test
   public void testCalculateYearlySalary() {
      employee.setName("Rajeev");
      employee.setAge(25);
      employee.setMonthlySalary(8000);
      double salary= empBusinessLogic.calculateYearlySalary(employee);
      assertEquals(96000, salary, 0.0);
   }
}

TestEmployeeDetails class is used for testing the methods of EmpBusinessLogic class. It

  • tests the yearly salary of the employee.

  • tests the appraisal amount of the employee.

Next, let's create a java class file name TestRunner.java in C:\ > JUNIT_WORKSPACE to execute Test case(s)

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(TestEmployeeDetails.class);
      for (Failure failure : result.getFailures()) {
         System.out.println(failure.toString());
      }
      System.out.println(result.wasSuccessful());
   }
} 

Compile the Test case and Test Runner classes using javac

C:\JUNIT_WORKSPACE>javac EmployeeDetails.java 
EmpBusinessLogic.java TestEmployeeDetails.java TestRunner.java

Now run the Test Runner which will run test case defined in provided Test Case class.

C:\JUNIT_WORKSPACE>java TestRunner

Verify the output.

true

JUnit - Using Assertion

Assertion

All the assertion are in the Assert class.

public class Assert extends java.lang.Object

This class provides a set of assertion methods useful for writing tests. Only failed assertions are recorded. Some of the important methods of Assert class are:

S.N.Methods & Description
1void assertEquals(boolean expected, boolean actual)
Check that two primitives/Objects are equal
2void assertTrue(boolean expected, boolean actual)
Check that a condition is true
3void assertFalse(boolean condition)
Check that a condition is false
4void assertNotNull(Object object)
Check that an object isn't null.
5void assertNull(Object object)
Check that an object is null
6void assertSame(boolean condition)
The assertSame() methods tests if two object references point to the same object
7void assertNotSame(boolean condition)
The assertNotSame() methods tests if two object references not point to the same object
8void assertArrayEquals(expectedArray, resultArray);
The assertArrayEquals() method will test whether two arrays are equal to each other.

Let's try to cover all of the above mentioned methods in an example. Create a java class file name TestAssertions.java in C:\ > JUNIT_WORKSPACE

import org.junit.Test;
import static org.junit.Assert.*;

public class TestAssertions {

   @Test
   public void testAssertions() {
      //test data
      String str1 = new String ("abc");
      String str2 = new String ("abc");
      String str3 = null;
      String str4 = "abc";
      String str5 = "abc";
      int val1 = 5;
      int val2 = 6;
      String[] expectedArray = {"one", "two", "three"};
      String[] resultArray =  {"one", "two", "three"};

      //Check that two objects are equal
      assertEquals(str1, str2);

      //Check that a condition is true
      assertTrue (val1 < val2);

      //Check that a condition is false
      assertFalse(val1 > val2);

      //Check that an object isn't null
      assertNotNull(str1);

      //Check that an object is null
      assertNull(str3);

      //Check if two object references point to the same object
      assertSame(str4,str5);

      //Check if two object references not point to the same object
      assertNotSame(str1,str3);

      //Check whether two arrays are equal to each other.
      assertArrayEquals(expectedArray, resultArray);
   }
}

Next, let's create a java class file name TestRunner.java in C:\ > JUNIT_WORKSPACE to execute Test case(s)

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

public class TestRunner2 {
   public static void main(String[] args) {
      Result result = JUnitCore.runClasses(TestAssertions.class);
      for (Failure failure : result.getFailures()) {
         System.out.println(failure.toString());
      }
      System.out.println(result.wasSuccessful());
   }
} 

Compile the Test case and Test Runner classes using javac

C:\JUNIT_WORKSPACE>javac TestAssertions.java TestRunner.java

Now run the Test Runner which will run test case defined in provided Test Case class.

C:\JUNIT_WORKSPACE>java TestRunner

Verify the output.

true

Annotation

Annotations are like meta-tags that you can add to you code and apply them to methods or in class. These annotation in JUnit gives us information about test methods , which methods are going to run before & after test methods, which methods run before & after all the methods, which methods or class will be ignore during execution.

List of annotations and their meaning in JUnit :

S.N.Annotation & Description
1@Test
The Test annotation tells JUnit that the public void method to which it is attached can be run as a test case.
2@Before
Several tests need similar objects created before they can run. Annotating a public void method with @Before causes that method to be run before each Test method.
3@After
If you allocate external resources in a Before method you need to release them after the test runs. Annotating a public void method with @After causes that method to be run after the Test method.
4@BeforeClass
Annotating a public static void method with @BeforeClass causes it to be run once before any of the test methods in the class.
5@AfterClass
This will perform the method after all tests have finished. This can be used to perform clean-up activities.
6@Ignore
The Ignore annotation is used to ignore the test and that test will not be executed.

Create a java class file name JunitAnnotation.java in C:\ > JUNIT_WORKSPACE to test annotation

import org.junit.After;
import org.junit.AfterClass;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Ignore;
import org.junit.Test;

public class JunitAnnotation {
	
   //execute before class
   @BeforeClass
   public static void beforeClass() {
      System.out.println("in before class");
   }

   //execute after class
   @AfterClass
   public static void  afterClass() {
      System.out.println("in after class");
   }

   //execute before test
   @Before
   public void before() {
      System.out.println("in before");
   }
	
   //execute after test
   @After
   public void after() {
      System.out.println("in after");
   }
	
   //test case
   @Test
   public void test() {
      System.out.println("in test");
   }
	
   //test case ignore and will not execute
   @Ignore
   public void ignoreTest() {
      System.out.println("in ignore test");
   }
}

Next, let's create a java class file name TestRunner.java in C:\ > JUNIT_WORKSPACE to execute annotaions

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(JunitAnnotation.class);
      for (Failure failure : result.getFailures()) {
         System.out.println(failure.toString());
      }
      System.out.println(result.wasSuccessful());
   }
} 

Compile the Test case and Test Runner classes using javac

C:\JUNIT_WORKSPACE>javac JunitAnnotation.java TestRunner.java

Now run the Test Runner which will run test case defined in provided Test Case class.

C:\JUNIT_WORKSPACE>java TestRunner

Verify the output.

in before class
in before
in test
in after
in after class
true

JUnit - Execution Procedure

This tutorial explains the execution procedure of methods in JUnit which means that which method is called first and which one after that. Here is the execution procedure of the JUint test API methods with the example.

Create a java class file name JunitAnnotation.java in C:\ > JUNIT_WORKSPACE to test annotation

import org.junit.After;
import org.junit.AfterClass;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Ignore;
import org.junit.Test;

public class ExecutionProcedureJunit {
	
   //execute only once, in the starting 
   @BeforeClass
   public static void beforeClass() {
      System.out.println("in before class");
   }

   //execute only once, in the end
   @AfterClass
   public static void  afterClass() {
      System.out.println("in after class");
   }

   //execute for each test, before executing test
   @Before
   public void before() {
      System.out.println("in before");
   }
	
   //execute for each test, after executing test
   @After
   public void after() {
      System.out.println("in after");
   }
	
   //test case 1
   @Test
   public void testCase1() {
      System.out.println("in test case 1");
   }

   //test case 2
   @Test
   public void testCase2() {
      System.out.println("in test case 2");
   }
}

Next, let's create a java class file name TestRunner.java in C:\ > JUNIT_WORKSPACE to execute annotaions

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(ExecutionProcedureJunit.class);
      for (Failure failure : result.getFailures()) {
         System.out.println(failure.toString());
      }
      System.out.println(result.wasSuccessful());
   }
} 

Compile the Test case and Test Runner classes using javac

C:\JUNIT_WORKSPACE>javac ExecutionProcedureJunit.java TestRunner.java

Now run the Test Runner which will run test case defined in provided Test Case class.

C:\JUNIT_WORKSPACE>java TestRunner

Verify the output.

in before class
in before
in test case 1
in after
in before
in test case 2
in after
in after class

See the above output and this is how the JUnit execution procedure is.

  • First of all beforeClass() method execute only once

  • Lastly, the afterClass() method executes only once.

  • before() method executes for each test case but before executing the test case.

  • after() method executes for each test case but after the execution of test case

  • In between before() and after() each test case executes.

JUnit - Executing Tests

The test cases are executed using JUnitCore class. JUnitCore is a facade for running tests. It supports running JUnit 4 tests, JUnit 3.8.x tests, and mixtures. To run tests from the command line, run java org.junit.runner.JUnitCore <TestClass>. For one-shot test runs, use the static method runClasses(Class[]).

Following is the declaration for org.junit.runner.JUnitCore class:

public class JUnitCore extends java.lang.Object

Here we will see how can we execute the tests with the help of JUnitCore.

Create a Class

  • Create a java class to be tested say MessageUtil.java in C:\ > JUNIT_WORKSPACE

/*
* This class prints the given message on console.
*/
public class MessageUtil {

   private String message;

   //Constructor
   //@param message to be printed
   public MessageUtil(String message){
      this.message = message;
   }
      
   // prints the message
   public String printMessage(){
      System.out.println(message);
      return message;
   }   
}  

Create Test Case Class

  • Create a java test class say TestJunit.java.

  • Add a test method testPrintMessage() to your test class.

  • Add an Annotaion @Test to method testPrintMessage().

  • Implement the test condition and check the condition using assertEquals API of Junit.

Create a java class file name TestJunit.java in C:\ > JUNIT_WORKSPACE

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());
   }
}

Create Test Runner Class

Next, let's create a java class file name TestRunner.java in C:\ > JUNIT_WORKSPACE to execute Test case(s) which import the JUnitCore class and uses the runClasses() method which take the test class name as parameter.

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());
   }
}  	

Compile the Test case and Test Runner classes using javac

C:\JUNIT_WORKSPACE>javac MessageUtil.java TestJunit.java TestRunner.java

Now run the Test Runner which will run test case defined in provided Test Case class.

C:\JUNIT_WORKSPACE>java TestRunner

Verify the output.

Hello World
true

JUnit Suite Test

Test suite

Test suite means bundle a few unit test cases and run it together. In JUnit, both @RunWith and @Suite annotation are used to run the suite test. This tutorial will show you an example having two TestJunit1 & TestJunit2 test classes to run together using Test Suite.

Create a Class

Create a java class to be tested say MessageUtil.java in C:\ > JUNIT_WORKSPACE

/*
* This class prints the given message on console.
*/
public class MessageUtil {

   private String message;

   //Constructor
   //@param message to be printed
   public MessageUtil(String message){
      this.message = message; 
   }

   // prints the message
   public void printMessage(){
      System.out.println(message);
      return message;
   }   

   // add "Hi!" to the message
   public String salutationMessage(){
      message = "Hi!" + message;
      System.out.println(message);
      return message;
   }   
}  	

Create Test Case Classes

Create a java class file name TestJunit1.java in C:\ > JUNIT_WORKSPACE

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

public class TestJunit1 {

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

Create a java class file name TestJunit2.java in C:\ > JUNIT_WORKSPACE

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

public class TestJunit2 {

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

Create Test Suite Class

  • Create a java class.

  • Attach @RunWith(Suite.class) Annotation with class.

  • Add reference to Junit test classes using @Suite.SuiteClasses annotation

Create a java class file name TestSuite.java in C:\ > JUNIT_WORKSPACE to execute Test case(s)

import org.junit.runner.RunWith;
import org.junit.runners.Suite;
@RunWith(Suite.class)
@Suite.SuiteClasses({
   TestJunit1.class,
   TestJunit2.class
})
public class JunitTestSuite {   
}  	

Create Test Runner Class

Create a java class file name TestRunner.java in C:\ > JUNIT_WORKSPACE to execute Test case(s)

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(JunitTestSuite.class);
      for (Failure failure : result.getFailures()) {
         System.out.println(failure.toString());
      }
      System.out.println(result.wasSuccessful());
   }
}  	

Compile all java classes using javac

C:\JUNIT_WORKSPACE>javac MessageUtil.java TestJunit1.java 
TestJunit2.java JunitTestSuite.java TestRunner.java

Now run the Test Runner which will run test case defined in provided Test Case class.

C:\JUNIT_WORKSPACE>java TestRunner

Verify the output.

Inside testPrintMessage()
Robert
Inside testSalutationMessage()
Hi Robert
true

JUnit - Ignore Test

Sometimes it happens that our code is not ready and test case written to test that method/code will fail if run. The @Ignore annotation helps in this regards.

  • A test method annotated with @Ignore will not be executed.

  • If a test class is annotated with @Ignore then none of its test methods will be executed.

Now let's see @Ignore in action.

Create a Class

  • Create a java class to be tested say MessageUtil.java in C:\ > JUNIT_WORKSPACE

/*
* This class prints the given message on console.
*/
public class MessageUtil {

   private String message;

   //Constructor
   //@param message to be printed
   public MessageUtil(String message){
      this.message = message; 
   }

   // prints the message
   public String printMessage(){
      System.out.println(message);
      return message;
   }   

   // add "Hi!" to the message
   public String salutationMessage(){
      message = "Hi!" + message;
      System.out.println(message);
      return message;
   }   
}  

Create Test Case Class

  • Create a java test class say TestJunit.java.

  • Add a test methods testPrintMessage(),testSalutationMessage() to your test class.

  • Add an Annotaion @Ignore to method testPrintMessage().

Create a java class file name TestJunit.java in C:\ > JUNIT_WORKSPACE

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

public class TestJunit {

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

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

Create Test Runner Class

Create a java class file name TestRunner.java in C:\ > JUNIT_WORKSPACE to execute Test case(s)

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());
   }
}  	

Compile the MessageUtil, Test case and Test Runner classes using javac

C:\JUNIT_WORKSPACE>javac MessageUtil.java TestJunit.java TestRunner.java

Now run the Test Runner which will not run testPrintMessage() test case defined in provided Test Case class.

C:\JUNIT_WORKSPACE>java TestRunner

Verify the output. testPrintMessage() test case is not tested.

Inside testSalutationMessage()
Hi!Robert
true

Now update TestJunit in C:\ > JUNIT_WORKSPACE to ignore all test cases. Add @Ignore at class level

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

@Ignore
public class TestJunit {

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

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

Compile the Test case using javac

C:\JUNIT_WORKSPACE>javac TestJunit.java

Now run the Test Runner which will not run any test case defined in provided Test Case class.

C:\JUNIT_WORKSPACE>java TestRunner

Verify the output. No test case is tested.

true

JUnit - Time Test

Junit provides a handy option of Timeout. If a test case takes more time than specified number of milliseconds then Junit will automatically mark it as failed. The timeout parameter is used along with @Test annotation. Now let's see @Test(timeout) in action.

Create a Class

  • Create a java class to be tested say MessageUtil.java in C:\ > JUNIT_WORKSPACE.

  • Add a infinite while loop inside printMessage() method.

/*
* This class prints the given message on console.
*/
public class MessageUtil {

   private String message;

   //Constructor
   //@param message to be printed
   public MessageUtil(String message){
      this.message = message; 
   }

   // prints the message
   public void printMessage(){
      System.out.println(message);
      while(true);
   }   

   // add "Hi!" to the message
   public String salutationMessage(){
      message = "Hi!" + message;
      System.out.println(message);
      return message;
   }   
}  	

Create Test Case Class

  • Create a java test class say TestJunit.java.

  • Add timeout of 1000 to testPrintMessage() test case.

Create a java class file name TestJunit.java in C:\ > JUNIT_WORKSPACE

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

public class TestJunit {

   String message = "Robert";	
   MessageUtil messageUtil = new MessageUtil(message);
   
   @Test(timeout=1000)
   public void testPrintMessage() {	
      System.out.println("Inside testPrintMessage()");     
      messageUtil.printMessage();     
   }

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

Create Test Runner Class

Create a java class file name TestRunner.java in C:\ > JUNIT_WORKSPACE to execute Test case(s)

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());
   }
}  	

Compile the MessageUtil, Test case and Test Runner classes using javac

C:\JUNIT_WORKSPACE>javac MessageUtil.java TestJunit.java TestRunner.java

Now run the Test Runner which will run test cases defined in provided Test Case class.

C:\JUNIT_WORKSPACE>java TestRunner

Verify the output. testPrintMessage() test case will mark unit testing failed.

Inside testPrintMessage()
Robert
Inside testSalutationMessage()
Hi!Robert
testPrintMessage(TestJunit): test timed out after 1000 milliseconds
false

JUnit - Exceptions Test

Junit provides a option of tracing the Exception handling of code. You can test the code whether code throws desired exception or not. The expected parameter is used along with @Test annotation. Now let's see @Test(expected) in action.

Create a Class

  • Create a java class to be tested say MessageUtil.java in C:\ > JUNIT_WORKSPACE.

  • Add a error condition inside printMessage() method.

/*
* This class prints the given message on console.
*/
public class MessageUtil {

   private String message;

   //Constructor
   //@param message to be printed
   public MessageUtil(String message){
      this.message = message; 
   }

   // prints the message
   public void printMessage(){
      System.out.println(message);
      int a =0;
      int b = 1/a;
   }   

   // add "Hi!" to the message
   public String salutationMessage(){
      message = "Hi!" + message;
      System.out.println(message);
      return message;
   }   
}  	

Create Test Case Class

  • Create a java test class say TestJunit.java.

  • Add expected exception ArithmeticException to testPrintMessage() test case.

Create a java class file name TestJunit.java in C:\ > JUNIT_WORKSPACE

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

public class TestJunit {

   String message = "Robert";	
   MessageUtil messageUtil = new MessageUtil(message);
   
   @Test(expected = ArithmeticException.class)
   public void testPrintMessage() {	
      System.out.println("Inside testPrintMessage()");     
      messageUtil.printMessage();     
   }

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

Create Test Runner Class

Create a java class file name TestRunner.java in C:\ > JUNIT_WORKSPACE to execute Test case(s)

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());
   }
}  	

Compile the MessageUtil, Test case and Test Runner classes using javac

C:\JUNIT_WORKSPACE>javac MessageUtil.java TestJunit.java TestRunner.java

Now run the Test Runner which will run test cases defined in provided Test Case class.

C:\JUNIT_WORKSPACE>java TestRunner

Verify the output. testPrintMessage() test case will be passed.

Inside testPrintMessage()
Robert
Inside testSalutationMessage()
Hi!Robert
true

JUnit - Parameterized Test

Junit 4 has introduced a new feature Parameterized tests.Parameterized tests allow developer to run the same test over and over again using different values. There are five steps, that you need to follow to create Parameterized tests.

  • Annotate test class with @RunWith(Parameterized.class)

  • Create a public static method annotated with @Parameters that returns a Collection of Objects (as Array) as test data set.

  • Create a public constructor that takes in what is equivalent to one "row" of test data.

  • Create an instance variable for each "column" of test data.

  • Create your tests case(s) using the instance variables as the source of the test data.

The test case will be invoked once per each row of data. Let's see Parameterized tests in action.

Create a Class

  • Create a java class to be tested say PrimeNumberChecker.java in C:\ > JUNIT_WORKSPACE.

public class PrimeNumberChecker {
   public Boolean validate(final Integer primeNumber) {
      for (int i = 2; i < (primeNumber / 2); i++) {
         if (primeNumber % i == 0) {
            return false;
         }
      }
      return true;
   }
}

Create Parameterized Test Case Class

  • Create a java test class say PrimeNumberCheckerTest.java.

Create a java class file name PrimeNumberCheckerTest.java in C:\ > JUNIT_WORKSPACE

import java.util.Arrays;
import java.util.Collection;
 
import org.junit.Test;
import org.junit.Before;
import org.junit.runners.Parameterized;
import org.junit.runners.Parameterized.Parameters;
import org.junit.runner.RunWith;
import static org.junit.Assert.assertEquals;

@RunWith(Parameterized.class)
public class PrimeNumberCheckerTest {
   private Integer inputNumber;
   private Boolean expectedResult;
   private PrimeNumberChecker primeNumberChecker;

   @Before
   public void initialize() {
      primeNumberChecker = new PrimeNumberChecker();
   }

   // Each parameter should be placed as an argument here
   // Every time runner triggers, it will pass the arguments
   // from parameters we defined in primeNumbers() method
   public PrimeNumberCheckerTest(Integer inputNumber, 
      Boolean expectedResult) {
      this.inputNumber = inputNumber;
      this.expectedResult = expectedResult;
   }

   @Parameterized.Parameters
   public static Collection primeNumbers() {
      return Arrays.asList(new Object[][] {
         { 2, true },
         { 6, false },
         { 19, true },
         { 22, false },
         { 23, true }
      });
   }

   // This test will run 4 times since we have 5 parameters defined
   @Test
   public void testPrimeNumberChecker() {
      System.out.println("Parameterized Number is : " + inputNumber);
      assertEquals(expectedResult, 
      primeNumberChecker.validate(inputNumber));
   }
}

Create Test Runner Class

Create a java class file name TestRunner.java in C:\ > JUNIT_WORKSPACE to execute Test case(s)

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(PrimeNumberCheckerTest.class);
      for (Failure failure : result.getFailures()) {
         System.out.println(failure.toString());
      }
      System.out.println(result.wasSuccessful());
   }
}  	

Compile the PrimeNumberChecker, PrimeNumberCheckerTest and Test Runner classes using javac

C:\JUNIT_WORKSPACE>javac PrimeNumberChecker.java PrimeNumberCheckerTest.java
TestRunner.java

Now run the Test Runner which will run test cases defined in provided Test Case class.

C:\JUNIT_WORKSPACE>java TestRunner

Verify the output.

Parameterized Number is : 2
Parameterized Number is : 6
Parameterized Number is : 19
Parameterized Number is : 22
Parameterized Number is : 23
true

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