new file mode 100644
--- /dev/null
+++ b/proxy_force_ranges.t
@@ -0,0 +1,105 @@
+#!/usr/bin/perl
+
+# (C) Sergey Kandaurov
+# (C) Nginx, Inc.
+
+# Tests for http proxy cache and range filter.
+# proxy_force_ranges enables partial response regardless Accept-Ranges.
+
+###############################################################################
+
+use warnings;
+use strict;
+
+use Test::More;
+
+BEGIN { use FindBin; chdir($FindBin::Bin); }
+
+use lib 'lib';
+use Test::Nginx;
+
+###############################################################################
+
+select STDERR; $| = 1;
+select STDOUT; $| = 1;
+
+plan(skip_all => 'win32') if $^O eq 'MSWin32';
+
+my $t = Test::Nginx->new()->has(qw/http proxy cache/)
+	->write_file_expand('nginx.conf', <<'EOF');
+
+%%TEST_GLOBALS%%
+
+daemon off;
+
+events {
+}
+
+http {
+    %%TEST_GLOBALS_HTTP%%
+
+    proxy_cache_path   %%TESTDIR%%/cache  levels=1:2
+                       keys_zone=NAME:1m;
+
+    server {
+        listen       127.0.0.1:8080;
+        server_name  localhost;
+
+        location / {
+            proxy_pass    http://127.0.0.1:8081;
+        }
+
+        location /cache/ {
+            proxy_pass    http://127.0.0.1:8081/;
+            proxy_cache   NAME;
+            proxy_cache_valid 200 1m;
+
+            proxy_force_ranges on;
+        }
+    }
+
+    server {
+        listen       127.0.0.1:8081;
+        server_name  localhost;
+
+        location / {
+            max_ranges 0;
+        }
+    }
+}
+
+EOF
+
+$t->write_file('t.html', 'SEE-THIS');
+$t->try_run('no proxy_force_ranges')->plan(5);
+
+###############################################################################
+
+# serving range requests requires Accept-Ranges by default
+
+unlike(http_get_range('/t.html', 'Range: bytes=4-'), qr/^THIS/m,
+	'range without Accept-Ranges');
+
+like(http_get_range('/cache/t.html', 'Range: bytes=4-'), qr/^THIS/m,
+	'uncached range');
+like(http_get_range('/cache/t.html', 'Range: bytes=4-'), qr/^THIS/m,
+	'cached range');
+like(http_get_range('/cache/t.html', 'Range: bytes=0-2,4-'), qr/^SEE.*^THIS/ms,
+	'cached multipart range');
+
+like(`grep -F '[alert]' ${\($t->testdir())}/error.log`, qr/^$/s, 'no alerts');
+
+###############################################################################
+
+sub http_get_range {
+	my ($url, $extra) = @_;
+	return http(<<EOF);
+GET $url HTTP/1.1
+Host: localhost
+Connection: close
+$extra
+
+EOF
+}
+
+###############################################################################