diff --git a/test/built-ins/Array/prototype/flat/non-object-ctor-throws.js b/test/built-ins/Array/prototype/flat/non-object-ctor-throws.js
index 1d3e595cd33b28be34355e7696ab208bdfdde36a..2c47d6884bfc0ed5cd80deb18af8e331fb7273cf 100644
--- a/test/built-ins/Array/prototype/flat/non-object-ctor-throws.js
+++ b/test/built-ins/Array/prototype/flat/non-object-ctor-throws.js
@@ -8,6 +8,8 @@ description: >
 features: [Array.prototype.flat]
 ---*/
 
+assert.sameValue(typeof Array.prototype.flat, 'function');
+
 var a = [];
 a.constructor = null;
 assert.throws(TypeError, function() {
diff --git a/test/built-ins/Array/prototype/flat/null-undefined-input-throws.js b/test/built-ins/Array/prototype/flat/null-undefined-input-throws.js
index ee590d27a1e9f932d2b237f1e2b94e0f035775bc..807826e1bf172cdee622ad0669ba5cc6a939a660 100644
--- a/test/built-ins/Array/prototype/flat/null-undefined-input-throws.js
+++ b/test/built-ins/Array/prototype/flat/null-undefined-input-throws.js
@@ -7,6 +7,8 @@ description: >
 features: [Array.prototype.flat]
 ---*/
 
+assert.sameValue(typeof Array.prototype.flat, 'function');
+
 assert.throws(TypeError, function() {
   [].flat.call(null);
 }, 'null value');
diff --git a/test/built-ins/Array/prototype/flat/symbol-object-create-null-depth-throws.js b/test/built-ins/Array/prototype/flat/symbol-object-create-null-depth-throws.js
index a631efb34dbd9eb7137c2e0518949a75796bb77a..6df3a3bd85fa459874e0216de6ba4457aa5269e2 100644
--- a/test/built-ins/Array/prototype/flat/symbol-object-create-null-depth-throws.js
+++ b/test/built-ins/Array/prototype/flat/symbol-object-create-null-depth-throws.js
@@ -7,6 +7,8 @@ description: >
 features: [Array.prototype.flat]
 ---*/
 
+assert.sameValue(typeof Array.prototype.flat, 'function');
+
 assert.throws(TypeError, function() {
   [].flat(Symbol());
 }, 'symbol value');
diff --git a/test/built-ins/Array/prototype/flatMap/non-callable-argument-throws.js b/test/built-ins/Array/prototype/flatMap/non-callable-argument-throws.js
index ab0f8ca86dc0e201c889ebb0c25fdea2b95eef7e..aee6e4b6c016834e1ece528e7804a73458f7f27c 100644
--- a/test/built-ins/Array/prototype/flatMap/non-callable-argument-throws.js
+++ b/test/built-ins/Array/prototype/flatMap/non-callable-argument-throws.js
@@ -7,6 +7,8 @@ description: >
 features: [Array.prototype.flatMap]
 ---*/
 
+assert(Array.prototype.flatMap);
+
 assert.throws(TypeError, function() {
   [].flatMap({});
 }, 'non callable argument');
diff --git a/test/built-ins/Array/prototype/flatMap/non-object-ctor-throws.js b/test/built-ins/Array/prototype/flatMap/non-object-ctor-throws.js
index b54e27746a9a22c965fd866485892a742a61c4ff..39cc66e97debd942ca8e45e060f72347a78b2fc9 100644
--- a/test/built-ins/Array/prototype/flatMap/non-object-ctor-throws.js
+++ b/test/built-ins/Array/prototype/flatMap/non-object-ctor-throws.js
@@ -8,6 +8,8 @@ description: >
 features: [Array.prototype.flatMap]
 ---*/
 
+assert.sameValue(typeof Array.prototype.flatMap, 'function');
+
 var a = [];
 a.constructor = null;
 assert.throws(TypeError, function() {
diff --git a/test/built-ins/Array/prototype/flatMap/null-undefined-input-throws.js b/test/built-ins/Array/prototype/flatMap/null-undefined-input-throws.js
index dcfe81aaf4a89134288272631f58841defb08e35..44630d9644bf0b3ced9eacd985d78926fd38878d 100644
--- a/test/built-ins/Array/prototype/flatMap/null-undefined-input-throws.js
+++ b/test/built-ins/Array/prototype/flatMap/null-undefined-input-throws.js
@@ -7,6 +7,8 @@ description: >
 features: [Array.prototype.flatMap]
 ---*/
 
+assert.sameValue(typeof Array.prototype.flatMap, 'function');
+
 assert.throws(TypeError, function() {
   [].flatMap.call(null);
 }, 'null value');
diff --git a/test/built-ins/Array/prototype/flatMap/proxy-access-count.js b/test/built-ins/Array/prototype/flatMap/proxy-access-count.js
index 8b33348c6929e64fca5bd3bf1f095d08f8aca300..4e7edbd689361241c7e72b355fdaf7638b92775a 100644
--- a/test/built-ins/Array/prototype/flatMap/proxy-access-count.js
+++ b/test/built-ins/Array/prototype/flatMap/proxy-access-count.js
@@ -17,10 +17,12 @@ info: |
     b. Let exists be ? HasProperty(source, P).
     c. If exists is true, then
       i. Let element be ? Get(source, P).
-features: [Array.prototype.flat]
+features: [Array.prototype.flatMap]
 includes: [compareArray.js]
 ---*/
 
+assert.sameValue(typeof Array.prototype.flatMap, 'function');
+
 const getCalls = [], hasCalls = [];
 const handler = {
   get : function (t, p, r) { getCalls.push(p); return Reflect.get(t, p, r); },