new file mode 100644
--- /dev/null
+++ b/proxy_cache_revalidate.t
@@ -0,0 +1,120 @@
+#!/usr/bin/perl
+
+# (C) Maxim Dounin
+
+# Tests for http proxy cache revalidation with conditional requests.
+
+###############################################################################
+
+use warnings;
+use strict;
+
+use Test::More;
+use Socket qw/ CRLF /;
+
+BEGIN { use FindBin; chdir($FindBin::Bin); }
+
+use lib 'lib';
+use Test::Nginx qw/ :DEFAULT :gzip /;
+
+###############################################################################
+
+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=one:1m;
+
+    proxy_cache_revalidate on;
+
+    server {
+        listen       127.0.0.1:8080;
+        server_name  localhost;
+
+        location / {
+            proxy_pass    http://127.0.0.1:8081;
+            proxy_cache   one;
+
+            proxy_cache_valid  200  1s;
+
+            add_header X-Cache-Status $upstream_cache_status;
+        }
+    }
+
+    server {
+        listen       127.0.0.1:8081;
+        server_name  localhost;
+    }
+}
+
+EOF
+
+$t->write_file('t', 'SEE-THIS');
+$t->write_file('t2', 'SEE-THIS');
+
+eval {
+	open OLDERR, ">&", \*STDERR; close STDERR;
+	$t->run();
+	open STDERR, ">&", \*OLDERR;
+};
+plan(skip_all => 'no proxy_cache_revalidate') if $@;
+$t->plan(9);
+
+###############################################################################
+
+# request documents and make sure they are cached
+
+like(http_get('/t'), qr/X-Cache-Status: MISS.*SEE/ms, 'request');
+like(http_get('/t'), qr/X-Cache-Status: HIT.*SEE/ms, 'request cached');
+
+like(http_get('/t2'), qr/X-Cache-Status: MISS.*SEE/ms, '2nd request');
+like(http_get('/t2'), qr/X-Cache-Status: HIT.*SEE/ms, '2nd request cached');
+
+# wait for a while for cached responses to expire
+
+select undef, undef, undef, 2.5;
+
+# 1st document isn't modified, and should be revalidated on first request
+# (a 304 status code will appear in backend's logs), then cached again
+
+like(http_get('/t'), qr/X-Cache-Status: REVALIDATED.*SEE/ms, 'revalidated');
+like(read_file($t->testdir() . '/access.log'), qr/ 304 /, 'not modified');
+like(http_get('/t'), qr/X-Cache-Status: HIT.*SEE/ms, 'request cached');
+
+# 2nd document is recreated with a new content
+
+$t->write_file('t2', 'NEW');
+like(http_get('/t2'), qr/X-Cache-Status: EXPIRED.*NEW/ms, 'revalidate failed');
+like(http_get('/t2'), qr/X-Cache-Status: HIT.*NEW/ms, 'new response cached');
+
+###############################################################################
+
+sub read_file {
+	my ($file) = @_;
+	my $log;
+
+        local $/;
+
+        open LOG, $file or die "Can't open $file: $!\n";
+        $log = <LOG>;
+        close LOG;
+
+	return $log;
+}
+
+###############################################################################