new file mode 100644
--- /dev/null
+++ b/js_fetch_resolver.t
@@ -0,0 +1,234 @@
+#!/usr/bin/perl
+
+# (C) Dmitry Volyntsev
+# (C) Nginx, Inc.
+
+# Tests for http njs module, fetch method, dns support.
+
+###############################################################################
+
+use warnings;
+use strict;
+
+use Test::More;
+
+use IO::Select;
+
+BEGIN { use FindBin; chdir($FindBin::Bin); }
+
+use lib 'lib';
+use Test::Nginx;
+
+###############################################################################
+
+select STDERR; $| = 1;
+select STDOUT; $| = 1;
+
+plan(skip_all => '127.0.0.2 local address required')
+	unless defined IO::Socket::INET->new( LocalAddr => '127.0.0.2' );
+
+my $t = Test::Nginx->new()->has(qw/http/)
+	->write_file_expand('nginx.conf', <<'EOF');
+
+%%TEST_GLOBALS%%
+
+daemon off;
+
+events {
+}
+
+http {
+    %%TEST_GLOBALS_HTTP%%
+
+    js_import test.js;
+
+    server {
+        listen       127.0.0.1:8080;
+        server_name  localhost;
+
+        location /njs {
+            js_content test.njs;
+        }
+
+        location /dns {
+            js_content test.dns;
+
+            resolver   127.0.0.1:%%PORT_8981_UDP%%;
+            resolver_timeout 1s;
+        }
+    }
+
+    server {
+        listen       127.0.0.1:8080;
+        server_name  aaa;
+
+        location /loc {
+            js_content test.loc;
+        }
+    }
+
+    server {
+        listen       127.0.0.1:8080;
+        server_name  many;
+
+        location /loc {
+            js_content test.loc;
+        }
+    }
+}
+
+EOF
+
+my $p0 = port(8080);
+
+$t->write_file('test.js', <<EOF);
+    function test_njs(r) {
+        r.return(200, njs.version);
+    }
+
+    function dns(r) {
+        var url = `http://\${r.args.domain}:$p0/loc`;
+
+        ngx.fetch(url)
+        .then(reply => reply.text())
+        .then(body => r.return(200, body))
+        .catch(e => r.return(501, e.message))
+    }
+
+    function str(v) { return v ? v : ''};
+
+    function loc(r) {
+        var v = r.variables;
+        var body = str(r.requestText);
+        var foo = str(r.headersIn.foo);
+        var bar = str(r.headersIn.bar);
+        var c = r.headersIn.code ? Number(r.headersIn.code) : 200;
+        r.return(c, `\${v.host}:\${v.request_method}:\${foo}:\${bar}:\${body}`);
+    }
+
+     export default {njs: test_njs, dns, loc};
+EOF
+
+$t->try_run('no njs.fetch')->plan(3);
+
+$t->run_daemon(\&dns_daemon, port(8981), $t);
+$t->waitforfile($t->testdir . '/' . port(8981));
+
+###############################################################################
+
+local $TODO = 'not yet'
+	unless http_get('/njs') =~ /^([.0-9]+)$/m && $1 ge '0.5.1';
+
+like(http_get('/dns?domain=aaa'), qr/aaa:GET:::$/s, 'fetch dns aaa');
+like(http_get('/dns?domain=many'), qr/many:GET:::$/s, 'fetch dns many');
+like(http_get('/dns?domain=unknown'), qr/"unknown" could not be resolved/s,
+	'fetch dns unknown');
+
+###############################################################################
+
+sub reply_handler {
+	my ($recv_data, $port, %extra) = @_;
+
+	my (@name, @rdata);
+
+	use constant NOERROR	=> 0;
+	use constant FORMERR	=> 1;
+	use constant SERVFAIL	=> 2;
+	use constant NXDOMAIN	=> 3;
+
+	use constant A		=> 1;
+
+	use constant IN		=> 1;
+
+	# default values
+
+	my ($hdr, $rcode, $ttl) = (0x8180, NOERROR, 3600);
+
+	# decode name
+
+	my ($len, $offset) = (undef, 12);
+	while (1) {
+		$len = unpack("\@$offset C", $recv_data);
+		last if $len == 0;
+		$offset++;
+		push @name, unpack("\@$offset A$len", $recv_data);
+		$offset += $len;
+	}
+
+	$offset -= 1;
+	my ($id, $type, $class) = unpack("n x$offset n2", $recv_data);
+
+	my $name = join('.', @name);
+
+	if ($name eq 'aaa' && $type == A) {
+		push @rdata, rd_addr($ttl, '127.0.0.1');
+
+	} elsif ($name eq 'many' && $type == A) {
+		push @rdata, rd_addr($ttl, '127.0.0.2');
+		push @rdata, rd_addr($ttl, '127.0.0.1');
+	}
+
+	$len = @name;
+	pack("n6 (C/a*)$len x n2", $id, $hdr | $rcode, 1, scalar @rdata,
+		0, 0, @name, $type, $class) . join('', @rdata);
+}
+
+sub rd_addr {
+	my ($ttl, $addr) = @_;
+
+	my $code = 'split(/\./, $addr)';
+
+	return pack 'n3N', 0xc00c, A, IN, $ttl if $addr eq '';
+
+	pack 'n3N nC4', 0xc00c, A, IN, $ttl, eval "scalar $code", eval($code);
+}
+
+sub dns_daemon {
+	my ($port, $t, %extra) = @_;
+
+	my ($data, $recv_data);
+	my $socket = IO::Socket::INET->new(
+		LocalAddr => '127.0.0.1',
+		LocalPort => $port,
+		Proto => 'udp',
+	)
+		or die "Can't create listening socket: $!\n";
+
+	my $sel = IO::Select->new($socket);
+
+	local $SIG{PIPE} = 'IGNORE';
+
+	# signal we are ready
+
+	open my $fh, '>', $t->testdir() . '/' . $port;
+	close $fh;
+
+	while (my @ready = $sel->can_read) {
+		foreach my $fh (@ready) {
+			if ($socket == $fh) {
+				$fh->recv($recv_data, 65536);
+				$data = reply_handler($recv_data, $port);
+				$fh->send($data);
+
+			} else {
+				$fh->recv($recv_data, 65536);
+				unless (length $recv_data) {
+					$sel->remove($fh);
+					$fh->close;
+					next;
+				}
+
+again:
+				my $len = unpack("n", $recv_data);
+				$data = substr $recv_data, 2, $len;
+				$data = reply_handler($data, $port, tcp => 1);
+				$data = pack("n", length $data) . $data;
+				$fh->send($data);
+				$recv_data = substr $recv_data, 2 + $len;
+				goto again if length $recv_data;
+			}
+		}
+	}
+}
+
+###############################################################################