diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/collections/Map-get.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/collections/Map-get.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,41 @@
+// Map.prototype.get and .has basically work
+var m = new Map;
+
+function rope() {
+    var s = "s";
+    for (var i = 0; i < 16; i++)
+        s += s;
+    return s;
+}
+
+var keys = [undefined, null, true, false,
+            0, 1, 65535, 65536, 2147483647, 2147483648, 4294967295, 4294967296,
+            -1, -65536, -2147483648,
+            0.5, Math.sqrt(81), Math.PI,
+            Number.MAX_VALUE, -Number.MAX_VALUE, Number.MIN_VALUE, -Number.MIN_VALUE,
+            NaN, Infinity, -Infinity,
+            "", "\0", "a", "ab", "abcdefg", rope(),
+            {}, [], /a*b/, Object.prototype, Object];
+
+for (var i = 0; i < keys.length; i++) {
+    // without being set
+    var key = keys[i];
+    assertEq(m.has(key), false);
+    assertEq(m.get(key), undefined);
+
+    // after being set
+    var v = {};
+    assertEq(m.set(key, v), undefined);
+    assertEq(m.has(key), true);
+    assertEq(m.get(key), v);
+
+    // after being deleted
+    assertEq(m.delete(key), true);
+    assertEq(m.has(key), false);
+    assertEq(m.get(key), undefined);
+
+    m.set(key, v);
+}
+
+for (var i = 0; i < keys.length; i++)
+    assertEq(m.has(keys[i]), true);