[Tests] add more test coverage from tc39/test262#3755

.eslintrc

@@ -5,6 +5,7 @@
 
 	"rules": {
 		"id-length": 0,
+		"max-lines-per-function": 0,
 		"new-cap": [2, {
 			"capIsNewExceptions": [
 				"CodePointAt",

package.json

@@ -69,8 +69,11 @@
 		"es-value-fixtures": "^1.4.2",
 		"eslint": "=8.8.0",
 		"functions-have-names": "^1.2.3",
+		"has-bigints": "^1.0.2",
 		"has-strict-mode": "^1.0.1",
+		"has-symbols": "^1.0.3",
 		"in-publish": "^2.0.1",
+		"mock-property": "^1.0.0",
 		"npmignore": "^0.3.0",
 		"nyc": "^10.3.2",
 		"safe-publish-latest": "^2.0.0",

test/tests.js

@@ -3,6 +3,9 @@
 var v = require('es-value-fixtures');
 var forEach = require('for-each');
 var inspect = require('object-inspect');
+var mockProperty = require('mock-property');
+var hasSymbols = require('has-symbols')();
+var hasBigInts = require('has-bigints')();
 
 var SymbolDescriptiveString = require('es-abstract/2022/SymbolDescriptiveString');
 
@@ -13,6 +16,38 @@ var wholePoo = leadingPoo + trailingPoo;
 var replacementChar = '\uFFFD';
 
 module.exports = function (toWellFormed, t) {
+	t.test('does not call prototype toString methods on primitives', function (st) {
+		st.teardown(mockProperty(Boolean.prototype, 'toString', function fakeToString() {
+			st.fail('Boolean.prototype.toString should not be called');
+		}));
+		st.teardown(mockProperty(Number.prototype, 'toString', function fakeToString() {
+			st.fail('Number.prototype.toString should not be called');
+		}));
+		if (hasBigInts) {
+			st.teardown(mockProperty(BigInt.prototype, 'toString', function fakeToString() {
+				st.fail('BigInt.prototype.toString should not be called');
+			}));
+		}
+		if (hasSymbols) {
+			st.teardown(mockProperty(Symbol.prototype, 'toString', function fakeToString() {
+				st.fail('Symbol.prototype.toString should not be called');
+			}));
+		}
+
+		forEach(v.nonNullPrimitives, function (nonNullPrimitive) {
+			if (typeof nonNullPrimitive === 'symbol') {
+				st['throws'](
+					function () { toWellFormed(nonNullPrimitive); },
+					inspect(nonNullPrimitive) + ' throws when implicitly coerced to a string, and does not call the proto method'
+				);
+			} else if (typeof nonNullPrimitive !== 'string') {
+				st.equal(toWellFormed(nonNullPrimitive), String(nonNullPrimitive), inspect(nonNullPrimitive) + ' stringifies without calling the proto method');
+			}
+		});
+
+		st.end();
+	});
+
 	t.test('well-formed strings', function (st) {
 		forEach(v.nonStrings.concat(
 			v.strings,