Tests: added test for reading body from IO::Handle-like object.

test/perl/body_io_fake/psgi.pl

@@ -0,0 +1,11 @@
+use File::Basename;
+use lib dirname (__FILE__);
+use IOFake;
+
+my $app = sub {
+    my ($environ) = @_;
+
+    my $io = IOFake->new($environ->{'psgi.errors'});
+
+    return ['200', [ 'Content-Length' => '2' ], $io];
+};