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diff --git a/js/src/tests/test262/built-ins/FinalizationRegistry/prototype/unregister/unregister-cleaned-up-object-cell.js b/js/src/tests/test262/built-ins/FinalizationRegistry/prototype/unregister/unregister-cleaned-up-object-cell.js
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+++ b/js/src/tests/test262/built-ins/FinalizationRegistry/prototype/unregister/unregister-cleaned-up-object-cell.js
@@ -0,0 +1,64 @@
+// |reftest| skip-if(!this.hasOwnProperty('FinalizationRegistry')) async -- FinalizationRegistry is not enabled unconditionally
+// Copyright (C) 2019 Mathieu Hofman. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-finalization-registry.prototype.unregister
+description: >
+  Cannot unregister a cell referring to an Object that has been cleaned up
+info: |
+  FinalizationRegistry.prototype.cleanupSome ( [ _callback_ ] )
+  4. Perform ? CleanupFinalizationRegistry(_finalizationRegistry_, _callback_).
+
+  CleanupFinalizationRegistry ( _finalizationRegistry_ ):
+  3. While _finalizationRegistry_.[[Cells]] contains a Record _cell_ such that
+    _cell_.[[WeakRefTarget]] is ~empty~, then an implementation may perform the
+    following steps:
+    a. Choose any such _cell_.
+    b. Remove _cell_ from _finalizationRegistry_.[[Cells]].
+    c. Perform ? HostCallJobCallback(_callback_, *undefined*,
+      « _cell_.[[HeldValue]] »).
+
+  FinalizationRegistry.prototype.unregister ( _unregisterToken_ )
+  4. Let _removed_ be *false*.
+  5. For each Record { [[WeakRefTarget]], [[HeldValue]], [[UnregisterToken]] }
+    _cell_ of _finalizationRegistry_.[[Cells]], do
+    a. If _cell_.[[UnregisterToken]] is not ~empty~ and
+      SameValue(_cell_.[[UnregisterToken]], _unregisterToken_) is *true*, then
+      i. Remove _cell_ from _finalizationRegistry_.[[Cells]].
+      ii. Set _removed_ to *true*.
+  6. Return _removed_.
+features: [FinalizationRegistry.prototype.cleanupSome, FinalizationRegistry, host-gc-required]
+includes: [async-gc.js]
+flags: [async, non-deterministic]
+---*/
+
+var value = 'target!';
+var token = {};
+var finalizationRegistry = new FinalizationRegistry(function() {});
+
+function emptyCells() {
+  var target = {};
+  finalizationRegistry.register(target, value, token);
+
+  var prom = asyncGC(target);
+  target = null;
+
+  return prom;
+}
+
+emptyCells().then(function() {
+  var called = 0;
+  var holdings = [];
+  finalizationRegistry.cleanupSome(function cb(holding) {
+    called += 1;
+    holdings.push(holding);
+  });
+
+  assert.sameValue(called, 1);
+  assert.sameValue(holdings.length, 1);
+  assert.sameValue(holdings[0], value);
+
+  var res = finalizationRegistry.unregister(token);
+  assert.sameValue(res, false, 'unregister after iterating over it in cleanup');
+}).then($DONE, resolveAsyncGC);