Tests: added proxy cache tests with upstream cache headers.
diff --git a/proxy_cache_control.t b/proxy_cache_control.t
new file mode 100644
index 0000000..8ef60fc
--- /dev/null
+++ b/proxy_cache_control.t
@@ -0,0 +1,274 @@
+#!/usr/bin/perl
+
+# (C) Sergey Kandaurov
+# (C) Nginx, Inc.
+
+# Tests for proxy headers Expires / Cache-Control / X-Accel-Expires.
+
+###############################################################################
+
+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;
+
+my $t = Test::Nginx->new()->has(qw/http proxy cache rewrite/)->plan(19);
+
+$t->write_file_expand('nginx.conf', <<'EOF');
+
+%%TEST_GLOBALS%%
+
+daemon off;
+
+events {
+}
+
+http {
+    %%TEST_GLOBALS_HTTP%%
+
+    proxy_cache_path   %%TESTDIR%%/cache  keys_zone=NAME:1m;
+
+    server {
+        listen       127.0.0.1:8080;
+        server_name  localhost;
+
+        add_header  X-Cache-Status  $upstream_cache_status;
+
+        location / {
+            proxy_pass  http://127.0.0.1:8081;
+            proxy_cache NAME;
+
+            proxy_cache_background_update on;
+        }
+
+        location /ignore {
+            proxy_pass  http://127.0.0.1:8081;
+            proxy_cache NAME;
+
+            proxy_ignore_headers Cache-Control Expires;
+            proxy_ignore_headers X-Accel-Expires;
+        }
+    }
+
+    server {
+        listen       127.0.0.1:8081;
+        server_name  localhost;
+
+        location /expires {
+            add_header Expires "Thu, 31 Dec 2037 23:55:55 GMT";
+            return 204;
+        }
+
+        location /cache-control {
+            add_header Cache-Control max-age=60;
+            return 204;
+        }
+
+        location /x-accel-expires {
+            add_header X-Accel-Expires 60;
+            return 204;
+        }
+
+        location /x-accel-expires-at {
+            add_header X-Accel-Expires @60;
+            return 204;
+        }
+
+        location /x-accel-expires-duplicate {
+            add_header X-Accel-Expires 60;
+            add_header X-Accel-Expires 0;
+            return 204;
+        }
+
+        location /ignore {
+            add_header Expires "Thu, 31 Dec 2037 23:55:55 GMT";
+            add_header Cache-Control max-age=60;
+            add_header X-Accel-Expires 60;
+            return 204;
+        }
+
+        location /cache-control-before-expires {
+            add_header Cache-Control max-age=60;
+            add_header Expires "Thu, 01 Jan 1970 00:00:01 GMT";
+            return 204;
+        }
+
+        location /cache-control-after-expires {
+            add_header Expires "Thu, 01 Jan 1970 00:00:01 GMT";
+            add_header Cache-Control max-age=60;
+            return 204;
+        }
+
+        location /cache-control-no-cache-before-expires {
+            add_header Cache-Control no-cache;
+            add_header Expires "Thu, 31 Dec 2037 23:55:55 GMT";
+            return 204;
+        }
+
+        location /cache-control-no-cache-after-expires {
+            add_header Expires "Thu, 31 Dec 2037 23:55:55 GMT";
+            add_header Cache-Control no-cache;
+            return 204;
+        }
+
+        location /x-accel-expires-before {
+            add_header X-Accel-Expires 60;
+            add_header Expires "Thu, 01 Jan 1970 00:00:01 GMT";
+            add_header Cache-Control no-cache;
+            return 204;
+        }
+
+        location /x-accel-expires-after {
+            add_header Expires "Thu, 01 Jan 1970 00:00:01 GMT";
+            add_header Cache-Control no-cache;
+            add_header X-Accel-Expires 60;
+            return 204;
+        }
+
+        location /x-accel-expires-0-before {
+            add_header X-Accel-Expires 0;
+            add_header Cache-Control max-age=60;
+            add_header Expires "Thu, 31 Dec 2037 23:55:55 GMT";
+            return 204;
+        }
+
+        location /x-accel-expires-0-after {
+            add_header Cache-Control max-age=60;
+            add_header Expires "Thu, 31 Dec 2037 23:55:55 GMT";
+            add_header X-Accel-Expires 0;
+            return 204;
+        }
+
+        location /cache-control-no-cache-one {
+            add_header Cache-Control "no-cache, max-age=60";
+            return 204;
+        }
+
+        location /cache-control-no-cache-multi {
+            add_header Cache-Control no-cache;
+            add_header Cache-Control max-age=60;
+            return 204;
+        }
+
+        location /extension-before-x-accel-expires {
+            add_header Cache-Control stale-while-revalidate=2145902155;
+            add_header X-Accel-Expires  @1;
+            return 204;
+        }
+
+        location /extension-after-x-accel-expires {
+            add_header X-Accel-Expires @1;
+            add_header Cache-Control stale-while-revalidate=2145902155;
+            return 204;
+        }
+
+        location /set-cookie {
+            add_header Set-Cookie foo;
+            add_header Expires "Thu, 01 Jan 1970 00:00:01 GMT";
+            add_header Cache-control max-age=60;
+            return 204;
+        }
+    }
+}
+
+EOF
+
+$t->run();
+
+###############################################################################
+
+# cache headers work
+
+like(get('/expires'), qr/HIT/, 'expires');
+like(get('/cache-control'), qr/HIT/, 'cache-control');
+like(get('/x-accel-expires'), qr/HIT/, 'x-accel-expires');
+like(get('/x-accel-expires-at'), qr/EXPIRED/, 'x-accel-expires at');
+
+TODO: {
+local $TODO = 'not yet' unless $t->has_version('1.23.0');
+
+# the second header to disable cache is duplicate and ignored
+
+like(get('/x-accel-expires-duplicate'), qr/HIT/, 'x-accel-expires duplicate');
+
+}
+
+# with cache headers ignored, the response will be fresh
+
+like(get('/ignore'), qr/MISS/, 'cache headers ignored');
+
+# Cache-Control is preferred over Expires
+
+like(get('/cache-control-before-expires'), qr/HIT/,
+	'cache-control before expires');
+
+TODO: {
+local $TODO = 'not yet' unless $t->has_version('1.23.0');
+
+like(get('/cache-control-after-expires'), qr/HIT/,
+	'cache-control after expires');
+
+}
+
+like(get('/cache-control-no-cache-before-expires'), qr/MISS/,
+	'cache-control no-cache before expires');
+like(get('/cache-control-no-cache-after-expires'), qr/MISS/,
+	'cache-control no-cache after expires');
+
+# X-Accel-Expires is preferred over both Cache-Control and Expires
+
+like(get('/x-accel-expires-before'), qr/HIT/, 'x-accel-expires before');
+
+TODO: {
+local $TODO = 'not yet' unless $t->has_version('1.23.0');
+
+like(get('/x-accel-expires-after'), qr/HIT/, 'x-accel-expires after');
+
+}
+
+like(get('/x-accel-expires-0-before'), qr/MISS/, 'x-accel-expires 0 before');
+like(get('/x-accel-expires-0-after'), qr/MISS/, 'x-accel-expires 0 after');
+
+# "Cache-Control: no-cache" disables caching, no matter of "max-age"
+
+like(get('/cache-control-no-cache-one'), qr/MISS/,
+	'cache-control no-cache');
+like(get('/cache-control-no-cache-multi'), qr/MISS/,
+	'cache-control no-cache multi line');
+
+# Cache-Control extensions are preserved with X-Accel-Expires
+
+like(get('/extension-before-x-accel-expires'),
+	qr/STALE/, 'cache-control extensions before x-accel-expires');
+
+TODO: {
+local $TODO = 'not yet' unless $t->has_version('1.23.0');
+
+like(get('/extension-after-x-accel-expires'),
+	qr/STALE/, 'cache-control extensions after x-accel-expires');
+
+}
+
+# Set-Cookie is considered when caching with Cache-Control
+
+like(get('/set-cookie'), qr/MISS/, 'set-cookie not cached');
+
+###############################################################################
+
+sub get {
+	my ($uri) = @_;
+	http_get($uri);
+	http_get($uri);
+}
+
+###############################################################################