1 files changed, 58 insertions, 0 deletions
diff --git a/testing/web-platform/tests/js/builtins/weakrefs/cleanup-prevented-with-unregister.optional.any.js b/testing/web-platform/tests/js/builtins/weakrefs/cleanup-prevented-with-unregister.optional.any.js
new file mode 100644
index 0000000000..640f21e7f3
--- /dev/null
+++ b/testing/web-platform/tests/js/builtins/weakrefs/cleanup-prevented-with-unregister.optional.any.js
@@ -0,0 +1,58 @@
+// META: script=/common/gc.js
+// META: script=resources/maybe-garbage-collect.js
+// ├──> maybeGarbageCollectAndCleanupAsync
+// └──> resolveGarbageCollection
+/*---
+esid: sec-finalization-registry.prototype.cleanupSome
+info: |
+  FinalizationRegistry.prototype.cleanupSome ( [ callback ] )
+
+  1. Let finalizationRegistry be the this value.
+  2. If Type(finalizationRegistry) is not Object, throw a TypeError exception.
+  3. If finalizationRegistry does not have a [[Cells]] internal slot, throw a TypeError exception.
+  4. If callback is not undefined and IsCallable(callback) is false, throw a TypeError exception.
+  5. Perform ? CleanupFinalizationRegistry(finalizationRegistry, callback).
+  6. Return undefined.
+
+  FinalizationRegistry.prototype.unregister ( unregisterToken )
+
+  1. Let removed be false.
+  2. For each Record { [[Target]], [[Holdings]], [[UnregisterToken]] } cell that is an element of finalizationRegistry.[[Cells]], do
+    a. If SameValue(cell.[[UnregisterToken]], unregisterToken) is true, then
+      i. Remove cell from finalizationRegistry.[[Cells]].
+      ii. Set removed to true.
+  3. Return removed.
+---*/
+let token = {};
+let finalizationRegistry = new FinalizationRegistry(function() {});
+
+function emptyCells() {
+  let target = {};
+  finalizationRegistry.register(target, 'target!', token);
+
+  let prom = maybeGarbageCollectAndCleanupAsync(target);
+  target = null;
+
+  return prom;
+}
+
+promise_test(() => {
+  return (async () => {
+    assert_implements(
+      typeof FinalizationRegistry.prototype.cleanupSome === 'function',
+      'FinalizationRegistry.prototype.cleanupSome is not implemented.'
+    );
+
+    await emptyCells();
+    let called = 0;
+
+    let res = finalizationRegistry.unregister(token);
+    assert_equals(res, true, 'unregister target before iterating over it in cleanup');
+
+    finalizationRegistry.cleanupSome((holding) => {
+      called += 1;
+    });
+
+    assert_equals(called, 0, 'callback was not called');
+  })().catch(resolveGarbageCollection);
+}, 'Cleanup might be prevented with an unregister usage');