junit test for apache CommandLineParser example

Question

Here is an example code using apache CommandLineParser

public class Foo {

  public static void main(final String[] args) throws Exception {

    Options options = new Options();

    options.addOption("x",
            true, "comment for param x");

    options.addOption("y",
            true, "comment for param y");


    CommandLine commandLine = null;

    CommandLineParser parser = new PosixParser();

    try {
        commandLine = parser.parse(options, args);
    } catch (ParseException e) {
        throw new RuntimeException("Error parsing arguments!");
    }

    if (!commandLine.hasOption("x")) {
        throw new IllegalArgumentException("x"
                + " option is missing!");
    }

    String numberOfColumns = commandLine.getOptionValue("x");
 :
 :

}

JUNIT test code:

@Test
public void testFoo() throws Exception {

    args = new String[2];

    args[0] = "x" + "=" + "hello";

    args[1] = "y" + "=" + "world";

    Foo.main(args);

}

My problem/question:

CommandLineParser keeps complaining that "x option is missing!". So I believe, the way I am passing the parameter and its values to command line parser is wrong. I tried other ways as well.

    args[0] = "-x" + "=" + "hello";
    args[1] = "-y" + "=" + "world";

and also

    args[0] = "x" 
    args[1] = "hello";
    args[2] = "y" 
    args[3] = "world";

Can some one, tell me the correct format to pass the arguments and its values so as to succeed?

Thanks in advance.

Answer 1

As far as I know the arguments must start with a minus.

args[0] = "-x";
args[1] = "hello";
args[2] = "-y";
args[3] = "world";

Answer 2

Using this following to test input:

public class Main {
    public static void main(String...args) {
        System.out.println(Arrays.toString(args));
    }
}

The following shows examples of the of different inputs

INPUT: -x=hello -y=world

args[0]="-x=hello"
args[1]="-x=world"

INPUT: -x hello -y world

args[0]="-x"
args[1]="hello"
args[2]="-y"
args[3]="-world"