diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/collections/Map-clear-2.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/collections/Map-clear-2.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,17 @@
+// Clearing a Map removes its entries; the Map remains usable afterwards.
+
+var m = Map([["a", "b"], ["b", "c"]]);
+assertEq(m.size, 2);
+m.clear();
+assertEq(m.size, 0);
+assertEq(m.has("a"), false);
+assertEq(m.get("a"), undefined);
+assertEq(m.delete("a"), false);
+assertEq(m.has("b"), false);
+for (var pair of m)
+    throw "FAIL";  // shouldn't be any pairs
+
+m.set("c", "d");
+assertEq(m.size, 1);
+assertEq(m.has("a"), false);
+assertEq(m.has("b"), false);