michael@0: function f(v1, v2, value)
michael@0: {
michael@0:   var b = v1 != v2;
michael@0:   assertEq(b, value,
michael@0:            "failed: " + v1 + ", " + v2 + ": " + value);
michael@0: }
michael@0: 
michael@0: var obj = {};
michael@0: var emul = objectEmulatingUndefined();
michael@0: 
michael@0: f(obj, obj, false);
michael@0: f(obj, obj, false);
michael@0: f(emul, obj, true);
michael@0: f(emul, obj, true);
michael@0: f(obj, emul, true);
michael@0: f(obj, emul, true);
michael@0: f(Object.prototype, obj, true);
michael@0: f(Object.prototype, obj, true);
michael@0: f(emul, emul, false);
michael@0: f(objectEmulatingUndefined(), emul, true);
michael@0: f(objectEmulatingUndefined(), emul, true);
michael@0: f(emul, objectEmulatingUndefined(), true);
michael@0: f(emul, objectEmulatingUndefined(), true);