tests demostrating the edge case fixed in eed850.

Makefile.PL

@@ -9,6 +9,7 @@ requires 'Try::Tiny';
 recommends 'HTTP::Parser::XS';
 recommends 'EV';
 install_script 'bin/twiggy';
+test_requires 'Test::Requires';
 test_requires 'Test::More';
 test_requires 'Test::TCP';
 use_test_base;

t/deflater.t

@@ -0,0 +1,51 @@
+use strict;
+use warnings;
+use Test::More qw(no_diag);
+use Test::Requires qw( Plack::Middleware::Deflater LWP::UserAgent IO::Uncompress::Gunzip );
+use Test::TCP;
+use Plack::Loader;
+use Plack::Request;
+use HTTP::Response;
+use IO::Uncompress::Gunzip qw(gunzip $GunzipError);
+
+use Plack::App::File;
+
+use HTTP::Request::Common;
+
+my $app = Plack::App::File->new( root => 't')->to_app;
+$app = Plack::Middleware::Deflater->wrap($app);
+
+open my $f, '>', "t/deflater_test.txt" or die $!;
+print $f '1234567890' x 1000;
+close $f;
+
+END { unlink('t/deflater_test.txt') }
+
+test_tcp(
+    client => sub {
+        my $port = shift;
+
+        my $ua = LWP::UserAgent->new;
+        $ua->timeout(2);
+        my $req = GET ("http://localhost:$port/deflater_test.txt");
+        $req->header('Accept-Encoding', 'gzip');
+        my $res = $ua->request($req);
+        if ($res->is_success) {
+
+            gunzip \$res->content => \(my $output)
+               or die "gunzip failed: $GunzipError\n";
+            is(length($output), 10000);
+        }
+        else {
+            ok(0);
+        }
+    },
+    server => sub {
+        my $port = shift;
+        my $server = Plack::Loader->load('Twiggy', port => $port, host => '127.0.0.1');
+        $server->run($app);
+    },
+);
+
+done_testing();
+