StringWriter/StringIO for Perl

Question

I'm trying to write some unit tests for some communications code that writes to a socket. During testing I'd like to have my communications library write to a string, then I can compare the contents of the string to what I expect to be written.

In Java I'd use something like a StringWriter so that my communications code could write to the standard Writer interface and at the end I can just ask for all of the data that was written.

Is there an equivalent of this or Python's StringIO for Perl? Is something like this already built in?

Answer 1

Yes. Since v5.8 you can open an output handle directly to a scalar reference.

my $output;
open my $handle, '>', \$output;
print $handle "foo\n";
printf $handle "%d\n", 123;
close $handle;
print $output;   # => "foo\n123\n"

Answer 2

You can do similar things with IO::Stringy.