new file mode 100644
--- /dev/null
+++ b/proxy_cache_bypass.t
@@ -0,0 +1,104 @@
+#!/usr/bin/perl
+
+# (C) Maxim Dounin
+
+# Tests for http proxy cache, proxy_cache_bypass.
+
+###############################################################################
+
+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 shmem rewrite/)->plan(8)
+	->write_file_expand('nginx.conf', <<'EOF');
+
+%%TEST_GLOBALS%%
+
+daemon off;
+
+events {
+}
+
+http {
+    %%TEST_GLOBALS_HTTP%%
+
+    proxy_cache_path %%TESTDIR%%/cache keys_zone=one:1m;
+
+    server {
+        listen       127.0.0.1:8080;
+        server_name  localhost;
+
+        location / {
+            proxy_pass http://127.0.0.1:8081;
+
+            proxy_cache one;
+            proxy_cache_key $uri;
+            proxy_cache_bypass $arg_bypass;
+            proxy_cache_valid any 1y;
+
+            proxy_intercept_errors on;
+            error_page 404 = @fallback;
+        }
+
+        location @fallback {
+            return 403;
+        }
+
+        add_header X-Cache-Status $upstream_cache_status;
+    }
+
+    server {
+        listen       127.0.0.1:8081;
+        server_name  localhost;
+
+        location / {
+        }
+    }
+}
+
+EOF
+
+$t->write_file('t', 'SEE-THIS');
+
+$t->run();
+
+###############################################################################
+
+like(http_get('/t'), qr/SEE-THIS/, 'request');
+
+$t->write_file('t', 'NOOP');
+
+like(http_get('/t'), qr/SEE-THIS/, 'request cached');
+like(http_get('/t?bypass=1'), qr/NOOP/, 'cache bypassed');
+like(http_get('/t'), qr/NOOP/, 'cached after bypass');
+
+# ticket #827, cache item "error" field was not cleared
+# on cache bypass
+
+like(http_get('/t2'), qr/403 Forbidden/, 'intercepted error');
+
+$t->write_file('t2', 'NOOP');
+
+like(http_get('/t2'), qr/403 Forbidden/, 'error cached');
+like(http_get('/t2?bypass=1'), qr/NOOP/, 'error cache bypassed');
+
+TODO: {
+local $TODO = 'not yet';
+
+like(http_get('/t2'), qr/NOOP/, 'error cached after bypass');
+
+}
+
+###############################################################################