Clean up some existing constructor checks; eliminate duplicate checks

test/built-ins/BigInt/not-a-constructor.js

@@ -0,0 +1,27 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-ecmascript-standard-built-in-objects
+description: >
+  BigInt does not implement [[Construct]]
+info: |
+  ECMAScript Function Objects
+
+  Built-in function objects that are not identified as constructors do not
+  implement the [[Construct]] internal method unless otherwise specified in
+  the description of a particular function.
+includes: [isConstructor.js]
+features: [BigInt, Reflect.construct, arrow-function]
+---*/
+
+assert.sameValue(
+  isConstructor(BigInt),
+  false,
+  'isConstructor(BigInt) must return false'
+);
+
+assert.throws(TypeError, () => {
+  new BigInt(1n);
+}, '`new BigInt(1n)` throws TypeError');
+

test/built-ins/Date/prototype/toJSON/builtin.js

@@ -6,16 +6,19 @@ description: >
   Tests that Date.prototype.toJSON meets the requirements
   for built-in objects defined by the introduction of chapter 17 of
   the ECMAScript Language Specification.
-includes: [isConstructor.js]
 features: [Reflect.construct]
 ---*/
 
-var toJSON = Date.prototype.toJSON;
-
-assert(Object.isExtensible(toJSON));
-assert.sameValue(typeof toJSON, 'function');
-assert.sameValue(Object.prototype.toString.call(toJSON), '[object Function]');
-assert.sameValue(Object.getPrototypeOf(toJSON), Function.prototype);
-
-assert.sameValue(toJSON.hasOwnProperty('prototype'), false);
-assert.sameValue(isConstructor(toJSON), false);
+assert(Object.isExtensible(Date.prototype.toJSON), 'Object.isExtensible(Date.prototype.toJSON) must return true');
+assert.sameValue(typeof Date.prototype.toJSON, 'function', 'The value of `typeof Date.prototype.toJSON` is "function"');
+assert.sameValue(
+  Object.prototype.toString.call(Date.prototype.toJSON),
+  '[object Function]',
+  'Object.prototype.toString.call(Date.prototype.toJSON) must return "[object Function]"'
+);
+assert.sameValue(
+  Object.getPrototypeOf(Date.prototype.toJSON),
+  Function.prototype,
+  'Object.getPrototypeOf(Date.prototype.toJSON) must return the value of Function.prototype'
+);
+assert.sameValue(Date.prototype.toJSON.hasOwnProperty('prototype'), false, 'Date.prototype.toJSON.hasOwnProperty("prototype") must return false');

test/built-ins/JSON/parse/builtin.js

@@ -5,15 +5,24 @@ esid: sec-json.parse
 description: >
   Requirements for built-in functions, defined in introduction of chapter 17,
   are satisfied.
-includes: [isConstructor.js]
 features: [Reflect.construct]
 ---*/
 
 var parse = JSON.parse;
-assert(Object.isExtensible(parse));
-assert.sameValue(typeof parse, 'function');
-assert.sameValue(Object.prototype.toString.call(parse), '[object Function]');
-assert.sameValue(Object.getPrototypeOf(parse), Function.prototype);
-
-assert.sameValue(parse.hasOwnProperty('prototype'), false);
-assert.sameValue(isConstructor(parse), false);
+assert(Object.isExtensible(parse), 'Object.isExtensible(parse) must return true');
+assert.sameValue(typeof parse, 'function', 'The value of `typeof parse` is "function"');
+assert.sameValue(
+  Object.prototype.toString.call(parse),
+  '[object Function]',
+  'Object.prototype.toString.call("JSON.parse") must return "[object Function]"'
+);
+assert.sameValue(
+  Object.getPrototypeOf(parse),
+  Function.prototype,
+  'Object.getPrototypeOf("JSON.parse") must return the value of Function.prototype'
+);
+assert.sameValue(
+  parse.hasOwnProperty('prototype'),
+  false,
+  'parse.hasOwnProperty("prototype") must return false'
+);

test/built-ins/JSON/stringify/builtin.js

@@ -6,12 +6,22 @@ description: >
   Tests that JSON.stringify meets the requirements
   for built-in objects defined by the introduction of chapter 17 of
   the ECMAScript Language Specification.
-includes: [isConstructor.js]
 features: [Reflect.construct]
 ---*/
 
-assert(Object.isExtensible(JSON.stringify));
-assert.sameValue(Object.prototype.toString.call(JSON.stringify), '[object Function]');
-assert.sameValue(Object.getPrototypeOf(JSON.stringify), Function.prototype);
-assert.sameValue(JSON.stringify.hasOwnProperty('prototype'), false);
-assert.sameValue(isConstructor(JSON.stringify), false);
+assert(Object.isExtensible(JSON.stringify), 'Object.isExtensible(JSON.stringify) must return true');
+assert.sameValue(
+  Object.prototype.toString.call(JSON.stringify),
+  '[object Function]',
+  'Object.prototype.toString.call(JSON.stringify) must return "[object Function]"'
+);
+assert.sameValue(
+  Object.getPrototypeOf(JSON.stringify),
+  Function.prototype,
+  'Object.getPrototypeOf(JSON.stringify) must return the value of Function.prototype'
+);
+assert.sameValue(
+  JSON.stringify.hasOwnProperty('prototype'),
+  false,
+  'JSON.stringify.hasOwnProperty("prototype") must return false'
+);

test/built-ins/Object/prototype/isPrototypeOf/builtin.js

@@ -7,12 +7,25 @@ description: >
   Tests that Object.prototype.isPrototypeOf meets the requirements
   for built-in objects defined by the introduction of chapter 17 of
   the ECMAScript Language Specification.
-includes: [isConstructor.js]
 features: [Reflect.construct]
 ---*/
 
-assert(Object.isExtensible(Object.prototype.isPrototypeOf));
-assert.sameValue(Object.prototype.toString.call(Object.prototype.isPrototypeOf), "[object Function]");
-assert.sameValue(Object.getPrototypeOf(Object.prototype.isPrototypeOf), Function.prototype);
-assert.sameValue(Object.prototype.isPrototypeOf.hasOwnProperty("prototype"), false);
-assert.sameValue(isConstructor(Object.prototype.isPrototypeOf), false);
+assert(
+  Object.isExtensible(Object.prototype.isPrototypeOf),
+  'Object.isExtensible(Object.prototype.isPrototypeOf) must return true'
+);
+assert.sameValue(
+  Object.prototype.toString.call(Object.prototype.isPrototypeOf),
+  "[object Function]",
+  'Object.prototype.toString.call(Object.prototype.isPrototypeOf) must return "[object Function]"'
+);
+assert.sameValue(
+  Object.getPrototypeOf(Object.prototype.isPrototypeOf),
+  Function.prototype,
+  'Object.getPrototypeOf(Object.prototype.isPrototypeOf) must return the value of Function.prototype'
+);
+assert.sameValue(
+  Object.prototype.isPrototypeOf.hasOwnProperty("prototype"),
+  false,
+  'Object.prototype.isPrototypeOf.hasOwnProperty("prototype") must return false'
+);

test/built-ins/Promise/create-resolving-functions-reject.js

@@ -9,7 +9,7 @@ info: |
 
   ...
   7. Let reject be ! CreateBuiltinFunction(stepsReject, « [[Promise]], [[AlreadyResolved]] »).
-features: [Reflect.construct]
+features: [Reflect.construct, arrow-function]
 includes: [isConstructor.js]
 flags: [async]
 ---*/
@@ -20,9 +20,13 @@ Promise.resolve(1).then(function() {
 
 var then = Promise.prototype.then;
 Promise.prototype.then = function(resolve, reject) {
-  assert(!isConstructor(reject));
-  assert.sameValue(reject.length, 1);
-  assert.sameValue(reject.name, '');
+  assert.sameValue(isConstructor(reject), false, 'isConstructor(reject) must return false');
+  assert.throws(TypeError, () => {
+    new reject();
+  }, '`new reject()` throws TypeError');
+
+  assert.sameValue(reject.length, 1, 'The value of reject.length is 1');
+  assert.sameValue(reject.name, '', 'The value of reject.name is ""');
 
   return then.call(this, resolve, reject);
 };

test/built-ins/Promise/create-resolving-functions-resolve.js

@@ -9,7 +9,7 @@ info: |
 
   ...
   3. Let resolve be ! CreateBuiltinFunction(stepsResolve, « [[Promise]], [[AlreadyResolved]] »).
-features: [Reflect.construct]
+features: [Reflect.construct, arrow-function]
 includes: [isConstructor.js]
 flags: [async]
 ---*/
@@ -20,9 +20,13 @@ Promise.resolve(1).then(function() {
 
 var then = Promise.prototype.then;
 Promise.prototype.then = function(resolve, reject) {
-  assert(!isConstructor(resolve));
-  assert.sameValue(resolve.length, 1);
-  assert.sameValue(resolve.name, '');
+  assert.sameValue(isConstructor(resolve), false, 'isConstructor(resolve) must return false');
+  assert.throws(TypeError, () => {
+    new resolve();
+  }, '`new resolve()` throws TypeError');
+
+  assert.sameValue(resolve.length, 1, 'The value of resolve.length is 1');
+  assert.sameValue(resolve.name, '', 'The value of resolve.name is ""');
 
   return then.call(this, resolve, reject);
 };

test/built-ins/Promise/executor-function-not-a-constructor.js

@@ -10,7 +10,7 @@ info: |
     implement the [[Construct]] internal method unless otherwise specified
     in the description of a particular function.
 includes: [isConstructor.js]
-features: [Reflect.construct]
+features: [Reflect.construct, arrow-function]
 ---*/
 
 var executorFunction;
@@ -21,5 +21,14 @@ function NotPromise(executor) {
 }
 Promise.resolve.call(NotPromise);
 
-assert.sameValue(Object.prototype.hasOwnProperty.call(executorFunction, "prototype"), false);
-assert.sameValue(isConstructor(executorFunction), false);
+assert.sameValue(
+  Object.prototype.hasOwnProperty.call(executorFunction, "prototype"),
+  false,
+  'Object.prototype.hasOwnProperty.call(executorFunction, "prototype") must return false'
+);
+assert.sameValue(isConstructor(executorFunction), false, 'isConstructor(executorFunction) must return false');
+
+assert.throws(TypeError, () => {
+  new executorFunction();
+}, '`new executorFunction()` throws TypeError');
+

test/built-ins/Promise/prototype/finally/invokes-then-with-function.js

@@ -4,7 +4,7 @@
 author: Jordan Harband
 description: Promise.prototype.finally invokes `then` method
 esid: sec-promise.prototype.finally
-features: [Promise.prototype.finally, Reflect.construct]
+features: [Promise.prototype.finally, Reflect.construct, arrow-function]
 includes: [isConstructor.js]
 ---*/
 
@@ -13,16 +13,16 @@ var returnValue = {};
 var callCount = 0;
 var thisValue = null;
 var argCount = null;
-var firstArg = null;
-var secondArg = null;
+var resolve = null;
+var reject = null;
 
 target.then = function(a, b) {
   callCount += 1;
 
   thisValue = this;
   argCount = arguments.length;
-  firstArg = a;
-  secondArg = b;
+  resolve = a;
+  reject = b;
 
   return returnValue;
 };
@@ -30,31 +30,38 @@ target.then = function(a, b) {
 var originalFinallyHandler = function() {};
 var result = Promise.prototype.finally.call(target, originalFinallyHandler, 2, 3);
 
-assert.sameValue(callCount, 1, 'Invokes `then` method exactly once');
+assert.sameValue(callCount, 1, 'The value of `callCount` is 1');
 assert.sameValue(
   thisValue,
   target,
-  'Invokes `then` method with the instance as the `this` value'
+  'The value of `thisValue` is expected to equal the value of target'
 );
-assert.sameValue(argCount, 2, 'Invokes `then` method with exactly two single arguments');
+assert.sameValue(argCount, 2, 'The value of `argCount` is 2');
 assert.sameValue(
-  typeof firstArg,
+  typeof resolve,
   'function',
-  'Invokes `then` method with a function as the first argument'
+  'The value of `typeof resolve` is "function"'
 );
-assert.notSameValue(firstArg, originalFinallyHandler, 'Invokes `then` method with a different fulfillment handler');
-assert.sameValue(firstArg.length, 1, 'fulfillment handler has a length of 1');
-assert.sameValue(firstArg.name, '', 'fulfillment handler is anonymous');
-assert(!isConstructor(firstArg), 'fulfillment handler is not constructor');
+assert.notSameValue(resolve, originalFinallyHandler, 'The value of `resolve` is expected to not equal the value of `originalFinallyHandler`');
+assert.sameValue(resolve.length, 1, 'The value of resolve.length is 1');
+assert.sameValue(resolve.name, '', 'The value of resolve.name is ""');
+assert.sameValue(isConstructor(resolve), false, 'isConstructor(resolve) must return false');
+assert.throws(TypeError, () => {
+  new resolve();
+}, '`new resolve()` throws TypeError');
+
 
 assert.sameValue(
-  typeof secondArg,
+  typeof reject,
   'function',
-  'Invokes `then` method with a function as the second argument'
+  'The value of `typeof reject` is "function"'
 );
-assert.notSameValue(secondArg, originalFinallyHandler, 'Invokes `then` method with a different rejection handler');
-assert.sameValue(secondArg.length, 1, 'rejection handler has a length of 1');
-assert.sameValue(secondArg.name, '', 'rejection handler is anonymous');
-assert(!isConstructor(secondArg), 'rejection handler is not constructor');
+assert.notSameValue(reject, originalFinallyHandler, 'The value of `reject` is expected to not equal the value of `originalFinallyHandler`');
+assert.sameValue(reject.length, 1, 'The value of reject.length is 1');
+assert.sameValue(reject.name, '', 'The value of reject.name is ""');
+assert.sameValue(isConstructor(reject), false, 'isConstructor(reject) must return false');
+assert.throws(TypeError, () => {
+  new reject();
+}, '`new reject()` throws TypeError');
 
-assert.sameValue(result, returnValue, 'Returns the result of the invocation of `then`');
+assert.sameValue(result, returnValue, 'The value of `result` is expected to equal the value of returnValue');

test/built-ins/Promise/prototype/finally/rejected-observable-then-calls-argument.js

@@ -12,7 +12,7 @@ info: |
   9. Return ? Invoke(promise, "then", « thrower »).
 
   The "length" property of a Catch Finally function is 1.
-features: [Promise.prototype.finally, Reflect.construct]
+features: [Promise.prototype.finally, Reflect.construct, class, arrow-function]
 includes: [isConstructor.js]
 flags: [async]
 ---*/
@@ -40,11 +40,23 @@ var expected = [
 
 var then = Promise.prototype.then;
 Promise.prototype.then = function(resolve, reject) {
-  assert(!isConstructor(resolve));
-  assert.sameValue(resolve.length, expected[calls].length);
-  assert.sameValue(resolve.name, expected[calls].name);
+  assert.sameValue(isConstructor(reject), false, 'isConstructor(reject) must return false');
+  assert.throws(TypeError, () => {
+    new reject();
+  }, '`new reject()` throws TypeError');
+
+  assert.sameValue(
+    resolve.length,
+    expected[calls].length,
+    'The value of resolve.length is expected to equal the value of expected[calls].length'
+  );
+  assert.sameValue(
+    resolve.name,
+    expected[calls].name,
+    'The value of resolve.name is expected to equal the value of expected[calls].name'
+  );
   if (calls === 0) {
-    assert.throws(MyError, resolve);
+    assert.throws(MyError, resolve, '`resolve()` throws `MyError`');
   }
 
   calls += 1;

test/built-ins/Promise/prototype/finally/resolved-observable-then-calls-argument.js

@@ -12,7 +12,7 @@ info: |
   9. Return ? Invoke(promise, "then", « valueThunk »).
 
   The "length" property of a Then Finally function is 1.
-features: [Promise.prototype.finally, Reflect.construct]
+features: [Promise.prototype.finally, Reflect.construct, arrow-function]
 includes: [isConstructor.js]
 flags: [async]
 ---*/
@@ -31,11 +31,23 @@ var expected = [
 
 var then = Promise.prototype.then;
 Promise.prototype.then = function(resolve) {
-  assert(!isConstructor(resolve));
-  assert.sameValue(resolve.length, expected[calls].length);
-  assert.sameValue(resolve.name, expected[calls].name);
+  assert.sameValue(isConstructor(resolve), false, 'isConstructor(resolve) must return false');
+  assert.throws(TypeError, () => {
+    new resolve();
+  }, '`new resolve()` throws TypeError');
+
+  assert.sameValue(
+    resolve.length,
+    expected[calls].length,
+    'The value of resolve.length is expected to equal the value of expected[calls].length'
+  );
+  assert.sameValue(
+    resolve.name,
+    expected[calls].name,
+    'The value of resolve.name is expected to equal the value of expected[calls].name'
+  );
   if (calls === 0) {
-    assert.sameValue(resolve(), value);
+    assert.sameValue(resolve(), value, 'resolve() must return the value of value');
   }
   calls += 1;
   return then.call(this, resolve);

test/built-ins/Proxy/create-target-is-not-a-constructor.js

@@ -0,0 +1,31 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-proxycreate
+description: >
+    A Proxy exotic object only accepts a constructor call if target is
+    constructor.
+info: |
+    ProxyCreate ( target, handler )
+
+    If IsCallable(target) is true, then
+        Set P.[[Call]] as specified in 9.5.12.
+        If IsConstructor(target) is true, then
+            Set P.[[Construct]] as specified in 9.5.13.
+    ...
+
+    Runtime Semantics: EvaluateNew(constructProduction, arguments)
+
+    8. If IsConstructor (constructor) is false, throw a TypeError exception.
+includes: [isConstructor.js]
+features: [Proxy, Reflect.construct, arrow-function]
+---*/
+
+var proxy = new Proxy(eval, {});
+
+proxy(); // the Proxy object is callable
+
+assert.sameValue(isConstructor(proxy), false, 'isConstructor(proxy) must return false');
+assert.throws(TypeError, () => {
+  new proxy();
+}, '`new proxy()` throws TypeError');

test/built-ins/Proxy/create-target-is-not-constructor.js

@@ -1,29 +0,0 @@
-// Copyright (C) 2015 the V8 project authors. All rights reserved.
-// This code is governed by the BSD license found in the LICENSE file.
-/*---
-es6id: 9.5.15
-description: >
-    A Proxy exotic object only accepts a constructor call if target is
-    constructor.
-info: |
-    Proxy ( target, handler )
-
-    7. If IsCallable(target) is true, then
-        b. If target has a [[Construct]] internal method, then
-            i. Set the [[Construct]] internal method of P as specified in
-            9.5.14.
-    ...
-
-    12.3.3.1.1 Runtime Semantics: EvaluateNew(constructProduction, arguments)
-
-    8. If IsConstructor (constructor) is false, throw a TypeError exception.
-features: [Proxy]
----*/
-
-var p = new Proxy(eval, {});
-
-p(); // the Proxy object is callable
-
-assert.throws(TypeError, function() {
-  new p();
-});

test/built-ins/Proxy/revocable/builtin.js

@@ -5,14 +5,24 @@ esid: sec-proxy.revocable
 description: >
   Requirements for built-in functions, defined in introduction of chapter 17,
   are satisfied.
-includes: [isConstructor.js]
 features: [Proxy, Reflect.construct]
 ---*/
 
-assert(Object.isExtensible(Proxy.revocable));
-assert.sameValue(typeof Proxy.revocable, 'function');
-assert.sameValue(Object.prototype.toString.call(Proxy.revocable), '[object Function]');
-assert.sameValue(Object.getPrototypeOf(Proxy.revocable), Function.prototype);
+assert(Object.isExtensible(Proxy.revocable), 'Object.isExtensible(Proxy.revocable) must return true');
+assert.sameValue(typeof Proxy.revocable, 'function', 'The value of `typeof Proxy.revocable` is "function"');
+assert.sameValue(
+  Object.prototype.toString.call(Proxy.revocable),
+  '[object Function]',
+  'Object.prototype.toString.call(Proxy.revocable) must return "[object Function]"'
+);
+assert.sameValue(
+  Object.getPrototypeOf(Proxy.revocable),
+  Function.prototype,
+  'Object.getPrototypeOf(Proxy.revocable) must return the value of Function.prototype'
+);
 
-assert.sameValue(Proxy.revocable.hasOwnProperty('prototype'), false);
-assert.sameValue(isConstructor(Proxy.revocable), false);
+assert.sameValue(
+  Proxy.revocable.hasOwnProperty('prototype'),
+  false,
+  'Proxy.revocable.hasOwnProperty(\'prototype\') must return false'
+);

test/built-ins/Proxy/revocable/not-a-constructor.js

@@ -0,0 +1,23 @@
+// Copyright (C) 2020 Rick Waldron. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-ecmascript-standard-built-in-objects
+description: >
+  Proxy.revocable does not implement [[Construct]]
+info: |
+  ECMAScript Function Objects
+
+  Built-in function objects that are not identified as constructors do not
+  implement the [[Construct]] internal method unless otherwise specified in
+  the description of a particular function.
+includes: [isConstructor.js]
+features: [Reflect.construct, Reflect, arrow-function, Proxy]
+---*/
+
+assert.sameValue(isConstructor(Proxy.revocable), false, 'isConstructor(Proxy.revocable) must return false');
+
+assert.throws(TypeError, () => {
+  new Proxy.revocable({}, {});
+}, '`new Proxy.revocable({}, {})` throws TypeError');
+

test/built-ins/Proxy/revocable/revocation-function-not-a-constructor.js

@@ -10,10 +10,19 @@ info: |
     implement the [[Construct]] internal method unless otherwise specified
     in the description of a particular function.
 includes: [isConstructor.js]
-features: [Proxy, Reflect.construct]
+features: [Proxy, Reflect.construct, arrow-function]
 ---*/
 
 var revocationFunction = Proxy.revocable({}, {}).revoke;
 
-assert.sameValue(Object.prototype.hasOwnProperty.call(revocationFunction, "prototype"), false);
-assert.sameValue(isConstructor(revocationFunction), false);
+assert.sameValue(
+  Object.prototype.hasOwnProperty.call(revocationFunction, "prototype"),
+  false,
+  'Object.prototype.hasOwnProperty.call(revocationFunction, "prototype") must return false'
+);
+assert.sameValue(isConstructor(revocationFunction), false, 'isConstructor(revocationFunction) must return false');
+assert.throws(TypeError, () => {
+  new revocationFunction();
+}, '`new revocationFunction()` throws TypeError');
+
+