[Tests] add coverage from tc39/test262#4520

Author: ljharb

test/tests.js

@@ -96,4 +96,58 @@ module.exports = function (getOrInsertComputed, t) {
 
 		st.end();
 	});
+
+	t.test('test262: test/built-ins/WeakMap/prototype/getOrInsertComputed/check-state-after-callback-fn-throws', { skip: typeof WeakMap === 'undefined' }, function (st) {
+		var map = new WeakMap();
+		var obj0 = {};
+		var obj1 = {};
+		var obj2 = {};
+		var obj3 = {};
+		map.set(obj0, 'zero');
+		map.set(obj1, 'one');
+		map.set(obj2, 'two');
+
+		st['throws'](
+			function () {
+				map.getOrInsertComputed(Symbol('3'), function () {
+					throw new Error('throw in callback');
+				});
+			},
+			Error
+		);
+
+		// Check the values after throwing in callbackfn.
+		st.equal(map.get(obj0), 'zero');
+		st.equal(map.get(obj1), 'one');
+		st.equal(map.get(obj2), 'two');
+		st.equal(map.has(obj3), false);
+
+		st['throws'](function () {
+			map.getOrInsertComputed(obj3, function () {
+				map.set(obj1, 'mutated');
+				throw new Error('throw in callback');
+			});
+		}, Error);
+
+		// Check the values after throwing in callbackfn, with mutation.
+		st.equal(map.get(obj0), 'zero');
+		st.equal(map.get(obj1), 'mutated');
+		st.equal(map.get(obj2), 'two');
+		st.equal(map.has(obj3), false);
+
+		st['throws'](function () {
+			map.getOrInsertComputed(obj3, function () {
+				map.set(obj3, 'mutated');
+				throw new Error('throw in callback');
+			});
+		}, Error);
+
+		// Check the values after throwing in callbackfn, with mutation.
+		st.equal(map.get(obj0), 'zero');
+		st.equal(map.get(obj1), 'mutated');
+		st.equal(map.get(obj2), 'two');
+		st.equal(map.get(obj3), 'mutated');
+
+		st.end();
+	});
 };