new file mode 100644
--- /dev/null
+++ b/http_header_buffers.t
@@ -0,0 +1,115 @@
+#!/usr/bin/perl
+
+# (C) Maxim Dounin
+# (C) Nginx, Inc.
+
+# Tests for large_client_header_buffers directive.
+
+###############################################################################
+
+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 $t = Test::Nginx->new()->has(qw/http rewrite/)->plan(2)
+	->write_file_expand('nginx.conf', <<'EOF');
+
+%%TEST_GLOBALS%%
+
+daemon off;
+
+events {
+}
+
+http {
+    %%TEST_GLOBALS_HTTP%%
+
+    connection_pool_size 64;
+    client_header_buffer_size 64;
+
+    server {
+        listen       127.0.0.1:8080;
+        server_name  five;
+
+        large_client_header_buffers 5 128;
+
+        return 204;
+    }
+
+    server {
+        listen       127.0.0.1:8080;
+        server_name  ten;
+
+        large_client_header_buffers 10 128;
+
+        return 204;
+    }
+
+    server {
+        listen       127.0.0.1:8080;
+        server_name  one;
+
+        large_client_header_buffers 1 128;
+
+        return 204;
+    }
+}
+
+EOF
+
+$t->run();
+
+###############################################################################
+
+TODO: {
+todo_skip 'overflow', 2 unless $ENV{TEST_NGINX_UNSAFE};
+
+# if hc->busy is allocated before the virtual server is selected,
+# and then additional buffers are allocated in a virtual server with larger
+# number of buffers configured, hc->busy will be overflowed
+
+like(http(
+	"GET / HTTP/1.0" . CRLF .
+	"X-Foo: " . ("1234567890" x 10) . CRLF .
+	"Host: ten" . CRLF .
+	"X-Foo: " . ("1234567890" x 10) . CRLF .
+	"X-Foo: " . ("1234567890" x 10) . CRLF .
+	"X-Foo: " . ("1234567890" x 10) . CRLF .
+	"X-Foo: " . ("1234567890" x 10) . CRLF .
+	"X-Foo: " . ("1234567890" x 10) . CRLF . CRLF
+), qr/204|400/, 'additional buffers in virtual server');
+
+# for pipelined requests large header buffers are saved to hc->free;
+# it sized for number of buffers in the current virtual server, but
+# saves previously allocated buffers, and there may be more buffers if
+# allocatad before the virtual server was selected
+
+like(http(
+	"GET / HTTP/1.1" . CRLF .
+	"X-Foo: " . ("1234567890" x 10) . CRLF .
+	"X-Foo: " . ("1234567890" x 10) . CRLF .
+	"X-Foo: " . ("1234567890" x 10) . CRLF .
+	"X-Foo: " . ("1234567890" x 10) . CRLF .
+	"X-Foo: " . ("1234567890" x 10) . CRLF .
+	"Host: one" . CRLF . CRLF .
+	"GET / HTTP/1.1" . CRLF .
+	"Host: one" . CRLF .
+	"Connection: close" . CRLF . CRLF
+), qr/204/, 'pipelined with too many buffers');
+
+}
+
+###############################################################################