1 files changed, 50 insertions, 0 deletions
diff --git a/js/src/tests/test262/built-ins/FinalizationRegistry/prototype/unregister/custom-this.js b/js/src/tests/test262/built-ins/FinalizationRegistry/prototype/unregister/custom-this.js
new file mode 100644
index 0000000000..ac7157940e
--- /dev/null
+++ b/js/src/tests/test262/built-ins/FinalizationRegistry/prototype/unregister/custom-this.js
@@ -0,0 +1,50 @@
+// |reftest| skip-if(!this.hasOwnProperty('FinalizationRegistry')) -- FinalizationRegistry is not enabled unconditionally
+// Copyright (C) 2019 Leo Balter. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-finalization-registry.prototype.unregister
+description: Return values applying custom this
+info: |
+  FinalizationRegistry.prototype.unregister ( unregisterToken )
+
+  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 Type(unregisterToken) is not Object, throw a TypeError exception.
+  5. Let removed be false.
+  6. 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.
+  7. Return removed.
+features: [FinalizationRegistry]
+---*/
+
+var fn = function() {};
+var unregister = FinalizationRegistry.prototype.unregister;
+var finalizationRegistry = new FinalizationRegistry(fn);
+
+var target1 = {};
+var target2 = {};
+var target3 = {};
+var token1 = {};
+var token2 = {};
+
+assert.sameValue(unregister.call(finalizationRegistry, token1), false, 'unregistering token1 from empty finalizationRegistry');
+assert.sameValue(unregister.call(finalizationRegistry, token2), false, 'unregistering token2 from empty finalizationRegistry');
+
+finalizationRegistry.register(target1, undefined, token1);
+finalizationRegistry.register(target2, undefined, token2);
+finalizationRegistry.register(target3, undefined, token2);
+
+assert.sameValue(unregister.call(finalizationRegistry, target1), false, 'own target does not work on unregister, #1');
+assert.sameValue(unregister.call(finalizationRegistry, target2), false, 'own target does not work on unregister, #2');
+assert.sameValue(unregister.call(finalizationRegistry, target3), false, 'own target does not work on unregister, #3');
+
+assert.sameValue(unregister.call(finalizationRegistry, token1), true, 'unregistering token1 from finalizationRegistry');
+assert.sameValue(unregister.call(finalizationRegistry, token1), false, 'unregistering token1 again from finalizationRegistry');
+assert.sameValue(unregister.call(finalizationRegistry, token2), true, 'unregistering token2 to remove target2 and target3');
+assert.sameValue(unregister.call(finalizationRegistry, token2), false, 'unregistering token2 from empty finalizationRegistry');
+
+reportCompare(0, 0);