JUnit 4 Tutorial: Introcution (Hello World) - 2020

Java:

$ java -version
java version "1.7.0_65"
OpenJDK Runtime Environment (IcedTea 2.5.1) (7u65-2.5.1-4ubuntu1~0.14.04.2)
OpenJDK 64-Bit Server VM (build 24.65-b04, mixed mode)

JAVA_HOME:

$ which javac
/usr/bin/javac

$ readlink -f /usr/bin/javac
/usr/lib/jvm/java-7-openjdk-amd64/bin/javac

Add JAVA_HOME and System path to ~/.bashrc:

• Set JAVA_HOME, using the path just before the bin folder:

  export JAVA_HOME=/usr/lib/jvm/java-7-openjdk-amd64
  

• Append Java compiler location to System Path:

  export PATH=$PATH:$JAVA_HOME/bin/
  

Run shell:

source ~/.bashrc

Download latest version of JUnit jar file
from https://github.com/junit-team/junit/wiki/Download-and-Install.
At the time of writing this tutorial, 'junit-4.11.jar' is the latest stable version.

We need 'hamcrest-core-1.3.jar' as well.

Put them into ~/usr/local/JUNIT.

Set the JUNIT_HOME environment variable to point to the base directory location where JUNIT jar is stored:

export JUNIT_HOME=/usr/local/JUNIT

Set the CLASSPATH environment variable to point to the JUNIT jar location:

export CLASSPATH=$CLASSPATH:$JUNIT_HOME/junit-4.11.jar
export CLASSPATH=$CLASSPATH:$JUNIT_HOME/hamcrest-core-1.3.jar

We may need to give permission to those jar files:

sudo chmod +r *.jar

Run shell:

source ~/.bashrc

Create a java class file name TestJunit in ~/JUNIT/workspace:

import org.junit.Test;
import static org.junit.Assert.assertEquals;
public class TestJunit {
   @Test
   public void testString() {
      String str= "Junit, Hello world!" ;
      assertEquals("Junit, Hello world!",str);
   }
}

Create a java class file name TestRunner in ~/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());
   }
}  	

$ javac TestJunit.java TestRunner.java
$ java TestRunner
true

JUnit & Maven Tutorial