Index: test/common.js
===================================================================
new file mode 100644
--- /dev/null
+++ b/test/common.js
@@ -0,0 +1,41 @@
+/*
+ * This file is part of Adblock Plus <https://adblockplus.org/>,
+ * Copyright (C) 2006-present eyeo GmbH
+ *
+ * Adblock Plus is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ *
+ * Adblock Plus is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+"use strict";
+
+const {createSandbox} = require("./_common");
+
+let qualifySelector = null;
+
+exports.setUp = function(callback)
+{
+  let sandboxedRequire = createSandbox();
+  (
+    {qualifySelector} = sandboxedRequire("../lib/common")
+  );
+
+  callback();
+};
+
+exports.testQualifySelector = function(test)
+{
+  test.equal(qualifySelector("div.bar", "#foo"), "div#foo.bar");
+  test.equal(qualifySelector("body #foo", "div"), "body div#foo");
+  test.equal(qualifySelector(".3bcRuc4 *", "div"), ".3bcRuc4 div");
+
+  test.done();
+};