test: add regression test for 51586

Signed-off-by: Matteo Collina <[email protected]> PR-URL: #51491 Reviewed-By: Vinícius Lourenço Claro Cardoso <[email protected]> Reviewed-By: Marco Ippolito <[email protected]> Reviewed-By: Matthew Aitken <[email protected]> Reviewed-By: Rafael Gonzaga <[email protected]> Reviewed-By: Moshe Atlow <[email protected]> Reviewed-By: Franziska Hinkelmann <[email protected]> Reviewed-By: Benjamin Gruenbaum <[email protected]>

Author: mcollina

test/parallel/test-webstream-structured-clone-no-leftovers.mjs

@@ -0,0 +1,28 @@
+import'../common/index.mjs';
+import{test}from'node:test';
+importassertfrom'node:assert';
+
+test('do not leak promises',async()=>{
+constbuf=newUint8Array(1);
+constreadable=newReadableStream({
+start(controller){
+controller.enqueue(buf);
+controller.close();
+}
+});
+
+const[out1,out2]=readable.tee();
+constcloned=structuredClone(out2,{transfer: [out2]});
+
+forawait(constchunkofcloned){
+assert.deepStrictEqual(chunk,buf);
+}
+
+forawait(constchunkofout2){
+assert.deepStrictEqual(chunk,buf);
+}
+
+forawait(constchunkofout1){
+assert.deepStrictEqual(chunk,buf);
+}
+});