How to install/use JUnit?

Question

I have installed JUnit on my Ubuntu 11.04

sudo apt-get install junit

Then created a test file like:

import org.junit.*;

public class TestBasicLinkedList {
  @Test public void testCanAdd(String[] args) {
    BasicLinkedList<Integer> list = new BasicLinkedList();
    list.add(new BasicListNode<Integer>(1));
    assertTrue(list.size() == 1);
    assertTrue(list.getFirst().getElement().equals(1));
  }
}

Then tried running in terminal

java org.junit.runner.JUnitCore TestBasicLinkedList.java

Got:

Exception in thread "main" java.lang.NoClassDefFoundError: org/junit/runner/JUnitCore
Caused by: java.lang.ClassNotFoundException: org.junit.runner.JUnitCore
    at java.net.URLClassLoader$1.run(URLClassLoader.java:217)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
Could not find the main class: org.junit.runner.JUnitCore. Program will exit.

How do I use JUnit? Is there a better shorter way of using it than the long command java org.junit.runner.JUnitCore TestBasicLinkedList.java? Perhaps something like junit *.Tests.java maybe?

Answer 1

To get you up and running, this is a basic test case:

import junit.framework.TestCase;

public class TestBasicLinkedList extends TestCase {
  public void testTrue() {
    assertTrue(true);
  }
}

The test class should extend TestCase, and test methods should start with "test", accept no arguments and return void.

To compile:

javac -cp /usr/share/java/junit4.jar TestBasicLinkedList.java

To run:

java -cp /usr/share/java/junit4.jar:. org.junit.runner.JUnitCore TestBasicLinkedList

This is for JUnit 4; JUnit 3 uses different classes for executing tests (try junit.textui.TestRunner).

Answer 2

In general, JUnit (just like any Java library) needs to be on your classpath. I don't know where exactly Ubuntu stores junitX.jar, but you probably want something like this:

java -cp .:/usr/share/java/junit4-4.10.jar TestBasicLinkedList

You'll need to compile TestBasicLinkedList first.

Answer 3

sudo apt-get install junit4

• /usr/share/java/junit4.jar is a symlink to the latest junit4 version.
• /usr/share/java/junit.jar is a symlink to the latest junit3 version.

If your application requires that you to set $JUNIT_HOME:

mkdir ~/junit
ln -s /usr/share/java/junit4.jar ~/junit
ln -s /usr/share/java/hamcrest-core.jar ~/junit
export JUNIT_HOME=~/junit

If your application requires it to have it in your $CLASSPATH:

Just copy it into one of your application's classpath directories.