tests: added a test for ngx.pipe to cover the pipe reading.

ngx.pipe forgot to close pipe after dup2 which make the output
pipe won't be close for the child process which is a daemon.
So the nginx will never get the close event for the pipe.

Author: zhuizhuhaomeng

.travis.yml

@@ -18,6 +18,7 @@ addons:
     - cpanminus
     - axel
     - luarocks
+    - daemonize
 
 cache:
   directories:

t/pipe-stdout.t

@@ -1005,3 +1005,25 @@ stdout err: timeout
 lua pipe add timer for reading: 100(ms)
 --- no_error_log
 [error]
+
+
+
+=== TEST 35: start a daemon process
+--- config
+    location = /t {
+        content_by_lua_block {
+            local ngx_pipe = require "ngx.pipe"
+            local proc = ngx_pipe.spawn({"sh", "-c", "daemonize /usr/bin/sleep 30 >/dev/null 2>&1"})
+
+            local data, err = proc:stdout_read_all()
+            if not data then
+                ngx.say(err)
+            end
+
+            ngx.say("OK")
+        }
+    }
+--- response_body
+OK
+--- no_error_log
+[error]