diff --git a/test/language/expressions/class/private-methods/prod-private-async-generator.js b/test/language/expressions/class/private-methods/prod-private-async-generator.js
index 3c59cf207e2021448b8d626b3fb4685ea77a58fd..da9d06baf6c32fcc8f199d930375ea3ff4331226 100644
--- a/test/language/expressions/class/private-methods/prod-private-async-generator.js
+++ b/test/language/expressions/class/private-methods/prod-private-async-generator.js
@@ -4,7 +4,7 @@
 /*---
 description: Private Async Generator (private method definitions in a class expression)
 esid: prod-MethodDefinition
-features: [async-iteration]
+features: [async-iteration, class, class-methods-private]
 flags: [generated, async]
 info: |
     ClassElement :
@@ -77,8 +77,12 @@ var ctorPromise;
  * 2. the template provides c.ref/other.ref for external reference
  */
 
-function hasOwnProperty(obj, name) {
-  return Object.prototype.hasOwnProperty.call(obj, name);
+function hasProp(obj, name, expected, msg) {
+  var hasOwnProperty = Object.prototype.hasOwnProperty.call(obj, name);
+  assert.sameValue(hasOwnProperty, expected, msg);
+
+  var hasProperty = Reflect.has(obj, name);
+  assert.sameValue(hasProperty, expected, msg);
 }
 
 var C = class {
@@ -88,12 +92,9 @@ var C = class {
   get ref() { return this.#m; }
 
   constructor() {
-    assert.sameValue(
-      hasOwnProperty(this, '#m'), false,
-      'private methods are defined in an special internal slot and cannot be found as own properties'
-    );
+    hasProp(this, '#m', false, 'private methods are defined in an special internal slot and cannot be found as own properties');
     assert.sameValue(typeof this.#m, 'function');
-    assert.sameValue(this.ref(), this.#m, 'returns the same value');
+    assert.sameValue(this.ref, this.#m, 'returns the same value');
 
     var ctorIter = this.#m();
     var p = ctorIter.next();
@@ -109,20 +110,9 @@ var C = class {
 var c = new C();
 var other = new C();
 
-assert.sameValue(
-  hasOwnProperty(C.prototype, '#m'), false,
-  'method is not defined in the prototype'
-);
-
-assert.sameValue(
-  hasOwnProperty(C, '#m'), false,
-  'method is not defined in the contructor'
-);
-
-assert.sameValue(
-  hasOwnProperty(c, '#m'), false,
-  'method cannot be seen outside of the class'
-);
+hasProp(C.prototype, '#m', false, 'method is not defined in the prototype');
+hasProp(C, '#m', false, 'method is not defined in the contructor');
+hasProp(c, '#m', false, 'method cannot be seen outside of the class');
 
 /***
  * MethodDefinition : ClassElementName ( UniqueFormalParameters ) { FunctionBody }
@@ -134,6 +124,7 @@ assert.sameValue(c.ref, other.ref, 'The method is defined once, and reused on ev
 
 assert.sameValue(c.ref.name, '#m', 'function name is preserved external reference');
 ctorPromise.then(() => {
+    // gets the returned async iterator from #m
     var iter = c.ref();
     return iter.next().then(({ value, done }) => {
         assert.sameValue(value, 42, 'return from generator method');
diff --git a/test/language/expressions/class/private-methods/prod-private-async-method.js b/test/language/expressions/class/private-methods/prod-private-async-method.js
index 751c562834c0d8a7c95eeee69a0627a95451ffac..138a9e304b77a287c90c4cf37b810441c6eb6d3d 100644
--- a/test/language/expressions/class/private-methods/prod-private-async-method.js
+++ b/test/language/expressions/class/private-methods/prod-private-async-method.js
@@ -4,7 +4,7 @@
 /*---
 description: Private Async Method (private method definitions in a class expression)
 esid: prod-MethodDefinition
-features: [async-functions]
+features: [async-functions, class, class-methods-private]
 flags: [generated, async]
 info: |
     ClassElement :
@@ -77,8 +77,12 @@ var ctorPromise;
  * 2. the template provides c.ref/other.ref for external reference
  */
 
-function hasOwnProperty(obj, name) {
-  return Object.prototype.hasOwnProperty.call(obj, name);
+function hasProp(obj, name, expected, msg) {
+  var hasOwnProperty = Object.prototype.hasOwnProperty.call(obj, name);
+  assert.sameValue(hasOwnProperty, expected, msg);
+
+  var hasProperty = Reflect.has(obj, name);
+  assert.sameValue(hasProperty, expected, msg);
 }
 
 var C = class {
@@ -88,12 +92,9 @@ var C = class {
   get ref() { return this.#m; }
 
   constructor() {
-    assert.sameValue(
-      hasOwnProperty(this, '#m'), false,
-      'private methods are defined in an special internal slot and cannot be found as own properties'
-    );
+    hasProp(this, '#m', false, 'private methods are defined in an special internal slot and cannot be found as own properties');
     assert.sameValue(typeof this.#m, 'function');
-    assert.sameValue(this.ref(), this.#m, 'returns the same value');
+    assert.sameValue(this.ref, this.#m, 'returns the same value');
 
     assert.sameValue(this.#m.name, '#m', 'function name inside constructor');
     ctorPromise = this.#m().then(value => {
@@ -106,20 +107,9 @@ var C = class {
 var c = new C();
 var other = new C();
 
-assert.sameValue(
-  hasOwnProperty(C.prototype, '#m'), false,
-  'method is not defined in the prototype'
-);
-
-assert.sameValue(
-  hasOwnProperty(C, '#m'), false,
-  'method is not defined in the contructor'
-);
-
-assert.sameValue(
-  hasOwnProperty(c, '#m'), false,
-  'method cannot be seen outside of the class'
-);
+hasProp(C.prototype, '#m', false, 'method is not defined in the prototype');
+hasProp(C, '#m', false, 'method is not defined in the contructor');
+hasProp(c, '#m', false, 'method cannot be seen outside of the class');
 
 /***
  * MethodDefinition : ClassElementName ( UniqueFormalParameters ) { FunctionBody }
@@ -131,6 +121,7 @@ assert.sameValue(c.ref, other.ref, 'The method is defined once, and reused on ev
 
 assert.sameValue(c.ref.name, '#m', 'function name is preserved external reference');
 ctorPromise.then(() => {
+    // gets the returned promise from #m
     return c.ref().then(value => {
         assert.sameValue(value, 42, 'function return');
     });
diff --git a/test/language/expressions/class/private-methods/prod-private-generator.js b/test/language/expressions/class/private-methods/prod-private-generator.js
index c8f3458eddad8c7b2f09c0991639d4d8790f3ae2..6ca4547f7a4024153139c2ced3f3e376c4d50f95 100644
--- a/test/language/expressions/class/private-methods/prod-private-generator.js
+++ b/test/language/expressions/class/private-methods/prod-private-generator.js
@@ -4,7 +4,7 @@
 /*---
 description: Private Generator (private method definitions in a class expression)
 esid: prod-MethodDefinition
-features: [generators]
+features: [generators, class, class-methods-private]
 flags: [generated]
 info: |
     ClassElement :
@@ -75,8 +75,12 @@ info: |
  * 2. the template provides c.ref/other.ref for external reference
  */
 
-function hasOwnProperty(obj, name) {
-  return Object.prototype.hasOwnProperty.call(obj, name);
+function hasProp(obj, name, expected, msg) {
+  var hasOwnProperty = Object.prototype.hasOwnProperty.call(obj, name);
+  assert.sameValue(hasOwnProperty, expected, msg);
+
+  var hasProperty = Reflect.has(obj, name);
+  assert.sameValue(hasProperty, expected, msg);
 }
 
 var C = class {
@@ -86,12 +90,9 @@ var C = class {
   get ref() { return this.#m; }
 
   constructor() {
-    assert.sameValue(
-      hasOwnProperty(this, '#m'), false,
-      'private methods are defined in an special internal slot and cannot be found as own properties'
-    );
+    hasProp(this, '#m', false, 'private methods are defined in an special internal slot and cannot be found as own properties');
     assert.sameValue(typeof this.#m, 'function');
-    assert.sameValue(this.ref(), this.#m, 'returns the same value');
+    assert.sameValue(this.ref, this.#m, 'returns the same value');
 
     var res = this.#m().next();
     assert.sameValue(res.value, 42, 'return from generator method, inside ctor');
@@ -104,20 +105,9 @@ var C = class {
 var c = new C();
 var other = new C();
 
-assert.sameValue(
-  hasOwnProperty(C.prototype, '#m'), false,
-  'method is not defined in the prototype'
-);
-
-assert.sameValue(
-  hasOwnProperty(C, '#m'), false,
-  'method is not defined in the contructor'
-);
-
-assert.sameValue(
-  hasOwnProperty(c, '#m'), false,
-  'method cannot be seen outside of the class'
-);
+hasProp(C.prototype, '#m', false, 'method is not defined in the prototype');
+hasProp(C, '#m', false, 'method is not defined in the contructor');
+hasProp(c, '#m', false, 'method cannot be seen outside of the class');
 
 /***
  * MethodDefinition : ClassElementName ( UniqueFormalParameters ) { FunctionBody }
@@ -127,6 +117,7 @@ assert.sameValue(
  */
 assert.sameValue(c.ref, other.ref, 'The method is defined once, and reused on every new instance');
 
+// gets the returned iterator from #m
 var res = c.ref().next();
 assert.sameValue(res.value, 42, 'return from generator method');
 assert.sameValue(res.done, true, 'iterator is done');
diff --git a/test/language/expressions/class/private-methods/prod-private-method.js b/test/language/expressions/class/private-methods/prod-private-method.js
index 06fec13c01dde4594df6360bb9f26490b6a1f73c..66e45f39bde3507ab3758e01585fccf3bb7fc573 100644
--- a/test/language/expressions/class/private-methods/prod-private-method.js
+++ b/test/language/expressions/class/private-methods/prod-private-method.js
@@ -4,6 +4,7 @@
 /*---
 description: Private Method (private method definitions in a class expression)
 esid: prod-MethodDefinition
+features: [class, class-methods-private]
 flags: [generated]
 info: |
     ClassElement :
@@ -74,8 +75,12 @@ info: |
  * 2. the template provides c.ref/other.ref for external reference
  */
 
-function hasOwnProperty(obj, name) {
-  return Object.prototype.hasOwnProperty.call(obj, name);
+function hasProp(obj, name, expected, msg) {
+  var hasOwnProperty = Object.prototype.hasOwnProperty.call(obj, name);
+  assert.sameValue(hasOwnProperty, expected, msg);
+
+  var hasProperty = Reflect.has(obj, name);
+  assert.sameValue(hasProperty, expected, msg);
 }
 
 var C = class {
@@ -85,12 +90,9 @@ var C = class {
   get ref() { return this.#m; }
 
   constructor() {
-    assert.sameValue(
-      hasOwnProperty(this, '#m'), false,
-      'private methods are defined in an special internal slot and cannot be found as own properties'
-    );
+    hasProp(this, '#m', false, 'private methods are defined in an special internal slot and cannot be found as own properties');
     assert.sameValue(typeof this.#m, 'function');
-    assert.sameValue(this.ref(), this.#m, 'returns the same value');
+    assert.sameValue(this.ref, this.#m, 'returns the same value');
 
     assert.sameValue(this.#m(), 42, 'already defined in the ctor');
     assert.sameValue(this.#m.name, '#m', 'function name inside constructor');
@@ -101,20 +103,9 @@ var C = class {
 var c = new C();
 var other = new C();
 
-assert.sameValue(
-  hasOwnProperty(C.prototype, '#m'), false,
-  'method is not defined in the prototype'
-);
-
-assert.sameValue(
-  hasOwnProperty(C, '#m'), false,
-  'method is not defined in the contructor'
-);
-
-assert.sameValue(
-  hasOwnProperty(c, '#m'), false,
-  'method cannot be seen outside of the class'
-);
+hasProp(C.prototype, '#m', false, 'method is not defined in the prototype');
+hasProp(C, '#m', false, 'method is not defined in the contructor');
+hasProp(c, '#m', false, 'method cannot be seen outside of the class');
 
 /***
  * MethodDefinition : ClassElementName ( UniqueFormalParameters ) { FunctionBody }
@@ -124,5 +115,6 @@ assert.sameValue(
  */
 assert.sameValue(c.ref, other.ref, 'The method is defined once, and reused on every new instance');
 
+// gets the returned value from #m
 assert.sameValue(c.ref(), 42, 'function return');
 assert.sameValue(c.ref.name, '#m', 'function name is preserved external reference');
diff --git a/test/language/statements/class/private-methods/prod-private-async-generator.js b/test/language/statements/class/private-methods/prod-private-async-generator.js
index 2b64fb600335e816c4d93cfa2cae130d61e458e6..429175c04de2ef1530899531283683db0ba242aa 100644
--- a/test/language/statements/class/private-methods/prod-private-async-generator.js
+++ b/test/language/statements/class/private-methods/prod-private-async-generator.js
@@ -76,8 +76,12 @@ var ctorPromise;
  * the template provides c.ref() for external reference
  */
 
-function hasOwnProperty(obj, name) {
-  return Object.prototype.hasOwnProperty.call(obj, name);
+function hasProp(obj, name, expected, msg) {
+  var hasOwnProperty = Object.prototype.hasOwnProperty.call(obj, name);
+  assert.sameValue(hasOwnProperty, expected, msg);
+
+  var hasProperty = Reflect.has(obj, name);
+  assert.sameValue(hasProperty, expected, msg);
 }
 
 class C {
@@ -87,12 +91,9 @@ class C {
   get ref() { return this.#m; }
 
   constructor() {
-    assert.sameValue(
-      hasOwnProperty(this, '#m'), false,
-      'private methods are defined in an special internal slot and cannot be found as own properties'
-    );
+    hasProp(this, '#m', false, 'private methods are defined in an special internal slot and cannot be found as own properties');
     assert.sameValue(typeof this.#m, 'function');
-    assert.sameValue(this.ref(), this.#m, 'returns the same value');
+    assert.sameValue(this.ref, this.#m, 'returns the same value');
 
     var ctorIter = this.#m();
     var p = ctorIter.next();
@@ -108,20 +109,9 @@ class C {
 var c = new C();
 var other = new C();
 
-assert.sameValue(
-  hasOwnProperty(C.prototype, '#m'), false,
-  'method is not defined in the prototype'
-);
-
-assert.sameValue(
-  hasOwnProperty(C, '#m'), false,
-  'method is not defined in the contructor'
-);
-
-assert.sameValue(
-  hasOwnProperty(c, '#m'), false,
-  'method cannot be seen outside of the class'
-);
+hasProp(C.prototype, '#m', false, 'method is not defined in the prototype');
+hasProp(C, '#m', false, 'method is not defined in the contructor');
+hasProp(c, '#m', false, 'method cannot be seen outside of the class');
 
 /***
  * MethodDefinition : ClassElementName ( UniqueFormalParameters ) { FunctionBody }
@@ -133,6 +123,7 @@ assert.sameValue(c.ref, other.ref, 'The method is defined once, and reused on ev
 
 assert.sameValue(c.ref.name, '#m', 'function name is preserved external reference');
 ctorPromise.then(() => {
+    // gets the returned async iterator from #m
     var iter = c.ref();
     return iter.next().then(({ value, done }) => {
         assert.sameValue(value, 42, 'return from generator method');
diff --git a/test/language/statements/class/private-methods/prod-private-async-method.js b/test/language/statements/class/private-methods/prod-private-async-method.js
index 0ed2ea2e0816391137ff711a8375e605fa48a7a0..cf6a51180531d443620488909d91e2c07662d187 100644
--- a/test/language/statements/class/private-methods/prod-private-async-method.js
+++ b/test/language/statements/class/private-methods/prod-private-async-method.js
@@ -76,8 +76,12 @@ var ctorPromise;
  * the template provides c.ref() for external reference
  */
 
-function hasOwnProperty(obj, name) {
-  return Object.prototype.hasOwnProperty.call(obj, name);
+function hasProp(obj, name, expected, msg) {
+  var hasOwnProperty = Object.prototype.hasOwnProperty.call(obj, name);
+  assert.sameValue(hasOwnProperty, expected, msg);
+
+  var hasProperty = Reflect.has(obj, name);
+  assert.sameValue(hasProperty, expected, msg);
 }
 
 class C {
@@ -87,12 +91,9 @@ class C {
   get ref() { return this.#m; }
 
   constructor() {
-    assert.sameValue(
-      hasOwnProperty(this, '#m'), false,
-      'private methods are defined in an special internal slot and cannot be found as own properties'
-    );
+    hasProp(this, '#m', false, 'private methods are defined in an special internal slot and cannot be found as own properties');
     assert.sameValue(typeof this.#m, 'function');
-    assert.sameValue(this.ref(), this.#m, 'returns the same value');
+    assert.sameValue(this.ref, this.#m, 'returns the same value');
 
     assert.sameValue(this.#m.name, '#m', 'function name inside constructor');
     ctorPromise = this.#m().then(value => {
@@ -105,20 +106,9 @@ class C {
 var c = new C();
 var other = new C();
 
-assert.sameValue(
-  hasOwnProperty(C.prototype, '#m'), false,
-  'method is not defined in the prototype'
-);
-
-assert.sameValue(
-  hasOwnProperty(C, '#m'), false,
-  'method is not defined in the contructor'
-);
-
-assert.sameValue(
-  hasOwnProperty(c, '#m'), false,
-  'method cannot be seen outside of the class'
-);
+hasProp(C.prototype, '#m', false, 'method is not defined in the prototype');
+hasProp(C, '#m', false, 'method is not defined in the contructor');
+hasProp(c, '#m', false, 'method cannot be seen outside of the class');
 
 /***
  * MethodDefinition : ClassElementName ( UniqueFormalParameters ) { FunctionBody }
@@ -130,6 +120,7 @@ assert.sameValue(c.ref, other.ref, 'The method is defined once, and reused on ev
 
 assert.sameValue(c.ref.name, '#m', 'function name is preserved external reference');
 ctorPromise.then(() => {
+    // gets the returned promise from #m
     return c.ref().then(value => {
         assert.sameValue(value, 42, 'function return');
     });
diff --git a/test/language/statements/class/private-methods/prod-private-generator.js b/test/language/statements/class/private-methods/prod-private-generator.js
index c343e79bb79b311a6d61078ca1a79c772a94556e..ed87d4e3d4a1a4e58df069c3071cdfffcb404531 100644
--- a/test/language/statements/class/private-methods/prod-private-generator.js
+++ b/test/language/statements/class/private-methods/prod-private-generator.js
@@ -74,8 +74,12 @@ info: |
  * the template provides c.ref() for external reference
  */
 
-function hasOwnProperty(obj, name) {
-  return Object.prototype.hasOwnProperty.call(obj, name);
+function hasProp(obj, name, expected, msg) {
+  var hasOwnProperty = Object.prototype.hasOwnProperty.call(obj, name);
+  assert.sameValue(hasOwnProperty, expected, msg);
+
+  var hasProperty = Reflect.has(obj, name);
+  assert.sameValue(hasProperty, expected, msg);
 }
 
 class C {
@@ -85,12 +89,9 @@ class C {
   get ref() { return this.#m; }
 
   constructor() {
-    assert.sameValue(
-      hasOwnProperty(this, '#m'), false,
-      'private methods are defined in an special internal slot and cannot be found as own properties'
-    );
+    hasProp(this, '#m', false, 'private methods are defined in an special internal slot and cannot be found as own properties');
     assert.sameValue(typeof this.#m, 'function');
-    assert.sameValue(this.ref(), this.#m, 'returns the same value');
+    assert.sameValue(this.ref, this.#m, 'returns the same value');
 
     var res = this.#m().next();
     assert.sameValue(res.value, 42, 'return from generator method, inside ctor');
@@ -103,20 +104,9 @@ class C {
 var c = new C();
 var other = new C();
 
-assert.sameValue(
-  hasOwnProperty(C.prototype, '#m'), false,
-  'method is not defined in the prototype'
-);
-
-assert.sameValue(
-  hasOwnProperty(C, '#m'), false,
-  'method is not defined in the contructor'
-);
-
-assert.sameValue(
-  hasOwnProperty(c, '#m'), false,
-  'method cannot be seen outside of the class'
-);
+hasProp(C.prototype, '#m', false, 'method is not defined in the prototype');
+hasProp(C, '#m', false, 'method is not defined in the contructor');
+hasProp(c, '#m', false, 'method cannot be seen outside of the class');
 
 /***
  * MethodDefinition : ClassElementName ( UniqueFormalParameters ) { FunctionBody }
@@ -126,6 +116,7 @@ assert.sameValue(
  */
 assert.sameValue(c.ref, other.ref, 'The method is defined once, and reused on every new instance');
 
+// gets the returned iterator from #m
 var res = c.ref().next();
 assert.sameValue(res.value, 42, 'return from generator method');
 assert.sameValue(res.done, true, 'iterator is done');
diff --git a/test/language/statements/class/private-methods/prod-private-method.js b/test/language/statements/class/private-methods/prod-private-method.js
index 07d44da9c6d0f2e05acf7f8b8df84ef326dc01ca..151a639ea66226ce6013e6bf4adc7d36821137dc 100644
--- a/test/language/statements/class/private-methods/prod-private-method.js
+++ b/test/language/statements/class/private-methods/prod-private-method.js
@@ -74,8 +74,12 @@ info: |
  * the template provides c.ref() for external reference
  */
 
-function hasOwnProperty(obj, name) {
-  return Object.prototype.hasOwnProperty.call(obj, name);
+function hasProp(obj, name, expected, msg) {
+  var hasOwnProperty = Object.prototype.hasOwnProperty.call(obj, name);
+  assert.sameValue(hasOwnProperty, expected, msg);
+
+  var hasProperty = Reflect.has(obj, name);
+  assert.sameValue(hasProperty, expected, msg);
 }
 
 class C {
@@ -85,12 +89,9 @@ class C {
   get ref() { return this.#m; }
 
   constructor() {
-    assert.sameValue(
-      hasOwnProperty(this, '#m'), false,
-      'private methods are defined in an special internal slot and cannot be found as own properties'
-    );
+    hasProp(this, '#m', false, 'private methods are defined in an special internal slot and cannot be found as own properties');
     assert.sameValue(typeof this.#m, 'function');
-    assert.sameValue(this.ref(), this.#m, 'returns the same value');
+    assert.sameValue(this.ref, this.#m, 'returns the same value');
 
     assert.sameValue(this.#m(), 42, 'already defined in the ctor');
     assert.sameValue(this.#m.name, '#m', 'function name inside constructor');
@@ -101,20 +102,9 @@ class C {
 var c = new C();
 var other = new C();
 
-assert.sameValue(
-  hasOwnProperty(C.prototype, '#m'), false,
-  'method is not defined in the prototype'
-);
-
-assert.sameValue(
-  hasOwnProperty(C, '#m'), false,
-  'method is not defined in the contructor'
-);
-
-assert.sameValue(
-  hasOwnProperty(c, '#m'), false,
-  'method cannot be seen outside of the class'
-);
+hasProp(C.prototype, '#m', false, 'method is not defined in the prototype');
+hasProp(C, '#m', false, 'method is not defined in the contructor');
+hasProp(c, '#m', false, 'method cannot be seen outside of the class');
 
 /***
  * MethodDefinition : ClassElementName ( UniqueFormalParameters ) { FunctionBody }
@@ -124,5 +114,6 @@ assert.sameValue(
  */
 assert.sameValue(c.ref, other.ref, 'The method is defined once, and reused on every new instance');
 
+// gets the returned value from #m
 assert.sameValue(c.ref(), 42, 'function return');
 assert.sameValue(c.ref.name, '#m', 'function name is preserved external reference');