diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/error-toString.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/error-toString.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,9 @@
+var errorToString = Error.prototype.toString;
+
+
+assertEq(errorToString.call({message: "", name: ""}), "Error");
+assertEq(errorToString.call({name: undefined, message: ""}), "Error");
+assertEq(errorToString.call({name: "Test", message: undefined}), "Test");
+assertEq(errorToString.call({name: "Test", message: ""}), "Test");
+assertEq(errorToString.call({name: "", message: "Test"}), "Test");
+assertEq(errorToString.call({name: "Test", message: "it!"}), "Test: it!");