Add histogram_bucket test

t/023.histogram_buckets.t

@@ -0,0 +1,46 @@
+# vi:set ft=perl ts=4 sw=4 et fdm=marker:
+
+use Test::Nginx::Socket;
+use Fcntl;
+
+plan tests => repeat_each() * blocks() * 4;
+no_shuffle();
+run_tests();
+
+__DATA__
+
+=== TEST 1: access status with vhost_traffic_status_histogram_bucket to get the request and responseBuckets after accessing upstream backend
+--- http_config
+    vhost_traffic_status_zone;
+    vhost_traffic_status_histogram_buckets .1 .5 1 2;
+    upstream backend {
+	    server 127.0.0.1;
+    }
+    server {
+        server_name _;
+        vhost_traffic_status_filter_by_host on;
+    }
+--- config
+    location /status {
+        vhost_traffic_status_display;
+        vhost_traffic_status_display_format json;
+        access_log off;
+    }
+    location /one {
+        proxy_set_header Host one.example.org;
+        proxy_pass http://backend;
+    }
+--- user_files eval
+[
+    ['one/file.txt' => 'one.example.org:OK'],
+]
+--- request eval
+[
+    'GET /one/file.txt',
+    'GET /status/',
+]
+--- response_body_like eval
+[
+    'OK',
+    '\"requestBuckets\"\:\{\"msecs\"\:\[100,500,1000,2000\],\"counters\"\:\[1,1,1,1\].*\"responseBuckets\"\:\{\"msecs\"\:\[100,500,1000,2000\],\"counters\"\:\[1,1,1,1\]',
+]