Can a function in a module read the __DATA__ of the calling program?

I have a module which contains a function that reads a filehandle, $fh.

I'd like to write a test which tests that function. To do that, I need to provide it some sample data. I figured I would just drop a few lines into the __DATA__ section of the testing program, then point $fh at the *DATA handle and test away.

Unfortunately, it doesn't seem to work.

Here's what I'm trying (more or less):

$fh = *DATA;

my $results = $app->process();

is ( $results->{item1}, "result1", "process item1" );

__DATA__
item1,data1
item2,data2
item3,data3
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use vars qw($fh);

sub process {

    my ($self) = @_;

    my $reslts = {};

    while (<$fh>) {
        [do stuff]
        $results->{$key} = $result;
    }

    return $results;
}
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What basic bit of idiocy am I committing this time? :-)