Tests: Handle subdirectories in W3C tests

Ref gh-314

Author: scottgonzalez

package.json

@@ -38,7 +38,7 @@
     "rollup": "^0.29.0"
   },
   "web-platform-tests": {
-    "repo": "w3c/web-platform-tests#d12b850c1b6200757e9e19e794d268237c548b14",
+    "repo": "w3c/web-platform-tests#c5d333c859075744b3828a2a29057ee456234cb2",
     "path": "./tests/w3c"
   },
   "scripts": {

tests/support/pretest.js

@@ -88,6 +88,9 @@ function getFiles(tree) {
 
 function getTests(tree) {
 	return Promise.all(_.map(tree, function(object) {
+		if (object.type === 'tree') {
+			return Promise.resolve();
+		}
 		var $raw = getRaw(object.url);
 		return $raw.then(function(raw) {
 			return fs.outputFileAsync(path.join(testPath, object.path), raw, 'utf-8');