Here is the entire test class that tests private method Runner.parseArgsIntoLists, which is described in the article Testing Private Methods in JUnit and SuiteRunner.

/*
 * Copyright (C) 2001-2003 Artima Software, Inc. All rights reserved.
 * Licensed under the Open Software License version 1.0.
 *
 * A copy of the Open Software License version 1.0 is available at:
 *     http://www.artima.com/suiterunner/osl10.html
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of Artima Software, Inc. For more
 * information on Artima Software, Inc., please see:
 *     http://www.artima.com/
 */
package org.suiterunner;

import java.lang.Throwable;
import java.lang.reflect.Method;
import java.lang.reflect.InvocationTargetException;
import java.io.IOException;
import java.util.Date;
import java.util.List;
import java.util.ArrayList;

public class RunnerSuite extends Suite {

    private static void invokeStaticMethod(Class targetClass,
            String methodName, Class[] argClasses, Object[] argObjects)
            throws InvocationTargetException {

        try {
            Method method = targetClass.getDeclaredMethod(methodName,
                    argClasses);
            method.setAccessible(true);
            method.invoke(null, argObjects);
        }
        catch (NoSuchMethodException e) {
            // Should happen only rarely, because most times the
            // specified method should exist. If it does happen, just let
            // the test fail so the programmer can fix the problem.
            throw new TestFailedException(e);
        }
        catch (SecurityException e) {
            // Should happen only rarely, because the setAccessible(true)
            // should be allowed in when running unit tests. If it does
            // happen, just let the test fail so the programmer can fix
            // the problem.
            throw new TestFailedException(e);
        }
        catch (IllegalAccessException e) {
            // Should never happen, because setting accessible flag to
            // true. If setting accessible fails, should throw a security
            // exception at that point and never get to the invoke. But
            // just in case, wrap it in a TestFailedException and let a
            // human figure it out.
            throw new TestFailedException(e);
        }
        catch (IllegalArgumentException e) {
            // Should happen only rarerly, because usually the right
            // number and types of arguments will be passed. If it does
            // happen, just let the test fail so the programmer can fix
            // the problem.
            throw new TestFailedException(e);
        }
    }

    private static void invokeParseArgsIntoLists(String[] args,
            List runpathList, List reportersList, List suitesList)
            throws InvocationTargetException {

        // Purposely pass null values to the method, to make sure it throws
        // NullPointerException

        Class[] argClasses = {String[].class, List.class, List.class, List.class };
        Object[] argObjects = {args, runpathList, reportersList, suitesList };

        invokeStaticMethod(Runner.class, "parseArgsIntoLists", argClasses, argObjects);
    }


    public void testParseArgsIntoLists() throws InvocationTargetException {

        String[] args = new String[0];
        List runpathList = new ArrayList();
        List reportersList = new ArrayList();
        List suitesList = new ArrayList();

        try {
            invokeParseArgsIntoLists(null, runpathList, reportersList, suitesList);
            fail();
        }
        catch (InvocationTargetException e) {

            // throw the InvocationTargetException unless the target
            // exception is NullPointerException, which is expected
            Throwable targetException = e.getTargetException();
            if (!(targetException instanceof NullPointerException)) {
                throw e;
            }
        }

        try {
            invokeParseArgsIntoLists(args, null, reportersList, suitesList);
            fail();
        }
        catch (InvocationTargetException e) {

            // throw the InvocationTargetException unless the target
            // exception is NullPointerException, which is expected
            Throwable targetException = e.getTargetException();
            if (!(targetException instanceof NullPointerException)) {
                throw e;
            }
        }

        try {
            invokeParseArgsIntoLists(args, runpathList, null, suitesList);
            fail();
        }
        catch (InvocationTargetException e) {

            // throw the InvocationTargetException unless the target
            // exception is NullPointerException, which is expected
            Throwable targetException = e.getTargetException();
            if (!(targetException instanceof NullPointerException)) {
                throw e;
            }
        }

        try {
            invokeParseArgsIntoLists(args, runpathList, reportersList, null);
            fail();
        }
        catch (InvocationTargetException e) {

            // throw the InvocationTargetException unless the target
            // exception is NullPointerException, which is expected
            Throwable targetException = e.getTargetException();
            if (!(targetException instanceof NullPointerException)) {
                throw e;
            }
        }

        args = new String[7];
        args[0] = "-p";
        args[1] = "\"mydir\"";
        args[2] = "-g";
        args[3] = "-f";
        args[4] = "test.out";
        args[5] = "-s";
        args[6] = "MySuite";
        runpathList.clear();
        reportersList.clear();
        suitesList.clear();

        invokeParseArgsIntoLists(args, runpathList, reportersList,
                suitesList);

        verify(runpathList.size() == 2);
        verify(runpathList.get(0).equals(args[0]));
        verify(runpathList.get(1).equals(args[1]));

        verify(reportersList.size() == 3);
        verify(reportersList.get(0).equals(args[2]));
        verify(reportersList.get(1).equals(args[3]));
        verify(reportersList.get(2).equals(args[4]));

        verify(suitesList.size() == 2);
        verify(suitesList.get(0).equals(args[5]));
        verify(suitesList.get(1).equals(args[6]));

        args = new String[9];
        args[0] = "-p";
        args[1] = "\"mydir\"";
        args[2] = "-e";
        args[3] = "-o";
        args[4] = "-r";
        args[5] = "MyCustomReporter";
        args[6] = "-s";
        args[7] = "MySuite";
        args[8] = "MyOtherSuite";
        runpathList.clear();
        reportersList.clear();
        suitesList.clear();

        invokeParseArgsIntoLists(args, runpathList, reportersList,
                suitesList);

        verify(runpathList.size() == 2);
        verify(runpathList.get(0).equals(args[0]));
        verify(runpathList.get(1).equals(args[1]));

        verify(reportersList.size() == 4);
        verify(reportersList.get(0).equals(args[2]));
        verify(reportersList.get(1).equals(args[3]));
        verify(reportersList.get(2).equals(args[4]));
        verify(reportersList.get(3).equals(args[5]));

        verify(suitesList.size() == 3);
        verify(suitesList.get(0).equals(args[6]));
        verify(suitesList.get(1).equals(args[7]));
        verify(suitesList.get(2).equals(args[8]));

        args = new String[10];
        args[0] = "-p";
        args[1] = "\"serviceuitest-1.1beta4.jar myjini http://myhost:9998/myfile.jar\"";
        args[2] = "-g";
        args[3] = "-s";
        args[4] = "MySuite";
        args[5] = "MySecondSuite";
        args[6] = "MyThirdSuite";
        args[7] = "MyFourthSuite";
        args[8] = "MyFifthSuite";
        args[9] = "MySixthSuite";
        runpathList.clear();
        reportersList.clear();
        suitesList.clear();

        invokeParseArgsIntoLists(args, runpathList, reportersList,
                suitesList);

        verify(runpathList.size() == 2);
        verify(runpathList.get(0).equals(args[0]));
        verify(runpathList.get(1).equals(args[1]));

        verify(reportersList.size() == 1);
        verify(reportersList.get(0).equals(args[2]));

        verify(suitesList.size() == 7);
        verify(suitesList.get(0).equals(args[3]));
        verify(suitesList.get(1).equals(args[4]));
        verify(suitesList.get(2).equals(args[5]));
        verify(suitesList.get(3).equals(args[6]));
        verify(suitesList.get(4).equals(args[7]));
        verify(suitesList.get(5).equals(args[8]));
        verify(suitesList.get(6).equals(args[9]));
    }
}