Re: Another JUnit scenario

From:

=?ISO-8859-1?Q?Arne_Vajh=F8j?= <arne@vajhoej.dk>

Newsgroups:

comp.lang.java.programmer

Date:

Fri, 21 May 2010 16:45:56 -0400

Message-ID:

<4bf6f0f5$0$285$14726298@news.sunsite.dk>

On 21-05-2010 16:35, Arne Vajh?j wrote:

On 21-05-2010 16:25, Rhino wrote:

What is a good JUnit test for a method that takes no input parameters,
throws no exceptions, and returns no values but only writes
information to
a console?

In addition to the getLocales() method which we're discussing in another
thread, I have a displayLocales() method which begins by calling
getLocales
(), then writes the information it got from getLocales() to the console.

I'm at a loss in trying to think of something to test in a JUnit test for
this method.

Is there some way to prove that the console was written to? Is there some
way to intercept the output to be sure that the right things were
written?
Or that at least the right number of lines was written and a few of
the key
Locales appeared on the console? Or is none of that necessary for a
method
with these characteristics?

Because such a method is more demo style than library style,
then I am not sure that it is suited for unit testing at all.

But if you want to do it, then just catch output and compare
it to what you expect.

             PrintStream save = System.out;
             ByteArrayOutputStream baos = new ByteArrayOutputStream();
             PrintStream pw = new PrintStream(baos);
             System.setOut(pw);
             // do something
             System.setOut(save);
             pw.flush();
             // get output from baos.toString()

Arne