1 files changed, 84 insertions, 0 deletions
diff --git a/js/src/tests/test262/built-ins/Object/fromEntries/evaluation-order.js b/js/src/tests/test262/built-ins/Object/fromEntries/evaluation-order.js
new file mode 100644
index 0000000000..30677d6897
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Object/fromEntries/evaluation-order.js
@@ -0,0 +1,84 @@
+// Copyright (C) 2018 Kevin Gibbons. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-object.fromentries
+description: Evaluation order is iterator.next(), get '0', get '1', toPropertyKey, repeat.
+info: |
+  Object.fromEntries ( iterable )
+
+  ...
+  4. Let stepsDefine be the algorithm steps defined in CreateDataPropertyOnObject Functions.
+  5. Let adder be CreateBuiltinFunction(stepsDefine, « »).
+  6. Return ? AddEntriesFromIterable(obj, iterable, adder).
+
+includes: [compareArray.js]
+features: [Symbol.iterator, Object.fromEntries]
+---*/
+
+var effects = [];
+
+function makeEntry(label) {
+  return {
+    get '0'() {
+      effects.push('access property "0" of ' + label + ' entry');
+      return {
+        toString: function() {
+          effects.push('toString of ' + label + ' key');
+          return label + ' key';
+        },
+      };
+    },
+    get '1'() {
+      effects.push('access property "1" of ' + label + ' entry');
+      return label + ' value';
+    },
+  };
+}
+
+var iterable = {
+  [Symbol.iterator]: function() {
+    effects.push('get Symbol.iterator');
+    var count = 0;
+    return {
+      next: function() {
+        effects.push('next ' + count);
+        if (count === 0) {
+          ++count;
+          return {
+            done: false,
+            value: makeEntry('first', 'first key', 'first value'),
+          };
+        } else if (count === 1) {
+          ++count;
+          return {
+            done: false,
+            value: makeEntry('second', 'second key', 'second value'),
+          };
+        } else {
+          return {
+            done: true,
+          };
+        }
+      },
+    };
+  },
+};
+
+var result = Object.fromEntries(iterable);
+assert.compareArray(effects, [
+  'get Symbol.iterator',
+  'next 0',
+  'access property "0" of first entry',
+  'access property "1" of first entry',
+  'toString of first key',
+  'next 1',
+  'access property "0" of second entry',
+  'access property "1" of second entry',
+  'toString of second key',
+  'next 2',
+], 'Object.fromEntries evaluation order');
+assert.sameValue(result['first key'], 'first value');
+assert.sameValue(result['second key'], 'second value');
+
+reportCompare(0, 0);