test: fix dns test

Fix a few issues in test/internet/test-dns.js:
- 'hint' should be 'hints'
- reverse name lookup is not guaranteed to return 'localhost'
- V4MAPPED hint requires IPV6 address family

Signed-off-by: Timothy J Fontaine <tjfontaine@gmail.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/test/common.js b/test/common.js
index b83d98144..bd7318c95 100644
--- a/test/common.js
+++ b/test/common.js
@@ -289,3 +289,12 @@ exports.getServiceName = function getServiceName(port, protocol) {
 
   return serviceName;
 }
+
+exports.isValidHostname = function(str) {
+  // See http://stackoverflow.com/a/3824105
+  var re = new RegExp(
+    '^([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\\-]{0,61}[a-zA-Z0-9])' +
+    '(\\.([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\\-]{0,61}[a-zA-Z0-9]))*$');
+
+  return !!str.match(re) && str.length <= 255;
+}