Add tests for %WrapForValidIteratorPrototype%.return()

test/built-ins/Iterator/from/get-return-method-when-call-return.js

@@ -0,0 +1,29 @@
+// Copyright (C) 2024 Sosuke Suzuki. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-iterator.from
+description: >
+  Gets the base iterator return method when the wrapper return method is called.
+info: |
+  %WrapForValidIteratorPrototype%.return ( )
+    ...
+    5. Let returnMethod be ? GetMethod(iterator, "return").
+
+features: [iterator-helpers]
+flags: []
+---*/
+
+let returnGetCount = 0;
+const iter = {
+    get return() {
+        returnGetCount++;
+        return function () {
+            return { value: 5, done: true };
+        };
+    },
+};
+const wrapper = Iterator.from(iter);
+assert.sameValue(returnGetCount, 0);
+
+wrapper.return();
+assert.sameValue(returnGetCount, 1);

test/built-ins/Iterator/from/return-method-calls-base-return-method.js

@@ -0,0 +1,29 @@
+// Copyright (C) 2024 Sosuke Suzuki. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-iterator.from
+description: >
+  %WrapForValidIteratorPrototype%.return() call base iterator's return method when it exists.
+info: |
+  %WrapForValidIteratorPrototype%.return ( )
+    5. Let returnMethod be ? GetMethod(iterator, "return").
+    6. If returnMethod is undefined, then
+      ...
+    7. Return ? Call(returnMethod, iterator).
+
+includes: [deepEqual.js]
+features: [iterator-helpers]
+flags: []
+---*/
+
+let returnCallCount = 0;
+const iter = {
+    return () {
+        returnCallCount++;
+        return { value: 5, done: true };
+    },
+};
+const wrapper = Iterator.from(iter);
+
+assert.deepEqual(wrapper.return(), { value: 5, done: true });
+assert.sameValue(returnCallCount, 1);

test/built-ins/Iterator/from/return-method-returns-iterator-result.js

@@ -0,0 +1,22 @@
+// Copyright (C) 2024 Sosuke Suzuki. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-iterator.from
+description: >
+  %WrapForValidIteratorPrototype%.return() should return an iterator result object that value is undefined when base object does not have return method.
+info: |
+  %WrapForValidIteratorPrototype%.return ( )
+    ...
+    5. Let returnMethod be ? GetMethod(iterator, "return").
+    6. If returnMethod is undefined, then
+      a. Return CreateIterResultObject(undefined, true).
+
+includes: [deepEqual.js]
+features: [iterator-helpers]
+flags: []
+---*/
+
+const iter = {};
+const wrapper = Iterator.from(iter);
+
+assert.deepEqual(wrapper.return(), { value: undefined, done: true });

test/built-ins/Iterator/from/return-method-throws-for-invalid-this.js

@@ -0,0 +1,32 @@
+// Copyright (C) 2024 Sosuke Suzuki. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-iterator.from
+description: >
+  %WrapForValidIteratorPrototype%.return() requires [[iterated]] internal slot
+info: |
+  %WrapForValidIteratorPrototype%.return ( )
+    ...
+    2. Perform ? RequireInternalSlot(O, [[Iterated]]).
+
+features: [iterator-helpers]
+flags: []
+---*/
+
+const iter = {};
+const WrapForValidIteratorPrototype = Object.getPrototypeOf(Iterator.from(iter));
+
+assert.throws(TypeError, function() {
+    WrapForValidIteratorPrototype.return.call({});
+});
+
+let returnCallCount = 0;
+assert.throws(TypeError, function() {
+    WrapForValidIteratorPrototype.return.call({
+      return () {
+        returnCallCount++;
+        return { value: 5, done: true };
+      }
+    });
+});
+assert.sameValue(returnCallCount, 0);