diff --git a/.travis.yml b/.travis.yml
index 99c49b6..bc370e0 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,4 +1,6 @@
 sudo: false
 language: node_js
 node_js:
-  - 0.10
+  - 4
+  - 6
+  - 8
diff --git a/fs-mock.js b/fs-mock.js
index 84116c6..56d244e 100644
--- a/fs-mock.js
+++ b/fs-mock.js
@@ -530,7 +530,7 @@ LinkNode.prototype.isSymbolicLink = function () {
 };
 
 LinkNode.prototype._follow = function (via, memo) {
-    memo = memo || Set();
+    memo = memo || new Set();
     if (memo.has(this)) {
         var error = new Error("Can't follow symbolic link cycle at " + JSON.stringify(via));
         error.code = "ELOOP";
diff --git a/package.json b/package.json
index c8d7d9b..3913735 100644
--- a/package.json
+++ b/package.json
@@ -20,7 +20,7 @@
     "url": "http://github.com/kriskowal/q-io.git"
   },
   "dependencies": {
-    "collections": "^0.2.0",
+    "collections": "^5.1.3",
     "mime": "^1.2.11",
     "mimeparse": "^0.1.4",
     "q": "^1.0.1",
diff --git a/spec/http/basic-spec.js b/spec/http/basic-spec.js
index 88e09e1..7f69b89 100644
--- a/spec/http/basic-spec.js
+++ b/spec/http/basic-spec.js
@@ -90,6 +90,8 @@ describe("http server and client", function () {
         .finally(server.stop)
     });
 
+    // TODO If your unit-test depend network it's not unit test
+    // Error: getaddrinfo ENOTFOUND test.webdav.org test.webdav.org:80
     xit('should successfully access resources that require HTTP Basic authentication when using the username:password@host.com URL syntax', function(){
         // This tries to access a public resource, see http://test.webdav.org/
         //