diff -r 000000000000 -r 6474c204b198 toolkit/components/workerloader/tests/moduleB-dependency.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/components/workerloader/tests/moduleB-dependency.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,11 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+exports.B = true;
+exports.foo = "foo";
+
+// Side-effect to detect if we attempt to re-execute this module.
+if ("loadedB" in self) {
+  throw new Error("B has been evaluted twice");
+}
+self.loadedB = true;
\ No newline at end of file