tests: use MYSQL_SOCKET env var to define socketPath

Author: dresende

Readme.md

@@ -1321,7 +1321,9 @@ $ FILTER=unit npm test
 ### Running integration tests
 
 Set the environment variables `MYSQL_DATABASE`, `MYSQL_HOST`, `MYSQL_PORT`,
-`MYSQL_USER` and `MYSQL_PASSWORD`. Then run `npm test`.
+`MYSQL_USER` and `MYSQL_PASSWORD`. `MYSQL_SOCKET` can also be used in place
+of `MYSQL_HOST` and `MYSQL_PORT` to connect over a UNIX socket. Then run
+`npm test`.
 
 For example, if you have an installation of mysql running on localhost:3306
 and no password set for the `root` user, run:

test/common.js

@@ -146,10 +146,11 @@ common.getSSLConfig = function() {
 
 function mergeTestConfig(config) {
   config = common.extend({
-    host     : process.env.MYSQL_HOST,
-    port     : process.env.MYSQL_PORT,
-    user     : process.env.MYSQL_USER,
-    password : process.env.MYSQL_PASSWORD
+    host       : process.env.MYSQL_HOST,
+    port       : process.env.MYSQL_PORT,
+    user       : process.env.MYSQL_USER,
+    password   : process.env.MYSQL_PASSWORD,
+    socketPath : process.env.MYSQL_SOCKET
   }, config);
 
   return config;