[Junit-devel] How do I check for output from a method sent to the console via System.out.println?

[Janette W. <ja...@ca...>]

Hi, my apologies if this question appears twice... I sent it once to the 
mailing list and found out I have to subscribe to the list first.   So I 
subscribed and here's my question again.

My question is on testing a couple of Strings sent to the console.   e.g. 
I have this method:

        public static void usage() {
                System.out.println("Usage: BookStoreServer employeeID 
[seed]");
                System.out.println("where employeeID is from E0000 to 
E9999");
        }

The usage() method is called under some circumstances.

I wrote a JUnit test (see snippet below).   When StartServer.main() is 
called with 3 arguments, it should cause the usage() method above to be 
invoked and output messages to the console.  Question is, I don't know how 
to use assertEquals() or other means to
check that those message have indeed been sent to the console.

        public void testStartServerNumOfArgsMoreThanUpperBound(){
                String[] argsArray = {"E0001", "1234", 
"invalid3rdArgument"}; 
                StartServer.main(argsArray);
                //assertEquals("Usage: BookStoreServer employeeID 
[seed]");   // Have to figure out how to assert the output from usage()
        }


Appreciate any guidance, thanks.


Janette Wong