new file mode 100644
--- /dev/null
+++ b/trailers.t
@@ -0,0 +1,134 @@
+#!/usr/bin/perl
+
+# (C) Sergey Kandaurov
+# (C) Nginx, Inc.
+
+# Tests for trailers in headers filter module.
+
+###############################################################################
+
+use warnings;
+use strict;
+
+use Test::More;
+
+use Socket qw/ $CRLF /;
+
+BEGIN { use FindBin; chdir($FindBin::Bin); }
+
+use lib 'lib';
+use Test::Nginx;
+
+###############################################################################
+
+select STDERR; $| = 1;
+select STDOUT; $| = 1;
+
+my $t = Test::Nginx->new()->has(qw/http proxy/)
+	->write_file_expand('nginx.conf', <<'EOF');
+
+%%TEST_GLOBALS%%
+
+daemon off;
+
+events {
+}
+
+http {
+    %%TEST_GLOBALS_HTTP%%
+
+    server {
+        listen       127.0.0.1:8080;
+        server_name  localhost;
+
+        add_trailer  X-Var $host;
+        add_trailer  X-Always $host always;
+        add_trailer  X-Empty '';
+        add_trailer  X-Sent-HTTP $sent_http_accept_ranges;
+        add_trailer  X-Sent-Trailer $sent_trailer_x_var;
+        add_trailer  X-Complex $host:$host;
+
+        location /t1 {
+        }
+
+        location /nx {
+        }
+
+        location /header {
+            add_header X-Var foo;
+        }
+
+        location /empty {
+            add_trailer X-Var $host;
+        }
+
+        location /not_chunked {
+            chunked_transfer_encoding off;
+        }
+
+        location /proxy {
+            proxy_pass http://127.0.0.1:8080/t1;
+            add_trailer X-Length $upstream_response_length;
+        }
+    }
+}
+
+EOF
+
+$t->write_file('t1', 'SEE-THIS');
+$t->write_file('header', '');
+$t->try_run('no add_trailer')->plan(17);
+
+###############################################################################
+
+my $r;
+
+$r = get('/t1');
+like($r, qr/8${CRLF}SEE-THIS${CRLF}0${CRLF}(.+${CRLF}){5}$CRLF/, 'trailers');
+unlike($r, qr/X-Var.*SEE-THIS/s, 'not in headers');
+like($r, qr/X-Var: localhost/, 'add_trailer');
+like($r, qr/X-Always/, 'add_trailer always');
+like($r, qr/X-Sent-HTTP: bytes/, 'add_trailer sent_http');
+like($r, qr/X-Sent-Trailer: localhost/, 'add_trailer sent_trailer');
+like($r, qr/X-Complex: localhost:localhost/, 'add_trailer complex');
+unlike($r, qr/X-Empty/, 'add_trailer empty');
+
+$r = get('/nx');
+unlike($r, qr/X-Var/, 'add_trailer bad');
+like($r, qr/X-Always/, 'add_trailer bad always');
+
+like(get('/header'), qr/foo.*^0$CRLF.*X-Var: localhost/ms, 'header name');
+
+like(http_get('/t1'), qr/${CRLF}SEE-THIS$/, 'no trailers - http10');
+unlike(get('/not_chunked'), qr/X-Always/, 'no trailers - not chunked');
+unlike(head('/t1'), qr/X-Always/, 'no trailers - head');
+
+unlike(get('/empty'), qr/X-Var/, 'no trailers expected');
+
+$r = get('/proxy');
+like($r, qr/SEE-THIS.*X-Length: 8/ms, 'upstream response variable');
+unlike($r, qr/X-Var/, 'inheritance');
+
+###############################################################################
+
+sub get {
+	my ($uri) = @_;
+	http(<<EOF);
+GET $uri HTTP/1.1
+Host: localhost
+Connection: close
+
+EOF
+}
+
+sub head {
+	my ($uri) = @_;
+	http(<<EOF);
+HEAD $uri HTTP/1.1
+Host: localhost
+Connection: close
+
+EOF
+}
+
+###############################################################################