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function test(obj, expected) {
var result = "";
for (var s in obj) {
result += s + ",";
}
assertEq(result, expected);
}
function runTest(mutate, expectedAfter) {
var p = {px: 1, py: 2};
var o = Object.create(p);
o.x = 3;
o.y = 4;
var expectedBefore = "x,y,px,py,";
test(o, expectedBefore);
mutate(o, p);
test(o, expectedAfter);
}
function testAddElement() {
runTest((o,p) => { o[0] = 5; }, "0,x,y,px,py,");
}
function testAddProtoElement() {
runTest((o,p) => { p[0] = 5; }, "x,y,0,px,py,");
}
function testDelete() {
runTest((o,p) => { delete o.x; }, "y,px,py,");
}
function testProtoDelete() {
runTest((o,p) => { delete p.px; }, "x,y,py,");
}
function testMakeUnenumerable() {
runTest((o,p) => {
Object.defineProperty(o, "x", { value: 1, enumerable: false });
}, "y,px,py,");
}
function testMakeProtoUnenumerable() {
runTest((o,p) => {
Object.defineProperty(p, "px", { value: 1, enumerable: false });
}, "x,y,py,");
}
for (var i = 0; i < 10; i++) {
testAddElement();
testAddProtoElement();
testDelete();
testProtoDelete();
testMakeUnenumerable()
testMakeProtoUnenumerable()
}