Bug 1687401 [wpt PR 27236] - Streams: settle reader.[[closedPromise]]…

… before performing close/error steps of read requests, a=testonly

Automatic update from web-platform-tests
Streams: settle reader.[[closedPromise]] before performing close/error steps of read requests

Follows whatwg/streams#1102.
--

wpt-commits: 7e94a4bcb5bd6808e08ed8db46fa63751543db52
wpt-pr: 27236

UltraBlame original commit: 20f8538ad6904319bdc6519519173023ebab1f2b

testing/web-platform/tests/streams/readable-streams/async-iterator.any.js

@@ -4530,3 +4530,208 @@ preventCancel
 )
 ;
 }
+promise_test
+(
+async
+(
+)
+=
+>
+{
+const
+rs
+=
+new
+ReadableStream
+(
+{
+async
+start
+(
+c
+)
+{
+c
+.
+enqueue
+(
+'
+a
+'
+)
+;
+c
+.
+enqueue
+(
+'
+b
+'
+)
+;
+c
+.
+enqueue
+(
+'
+c
+'
+)
+;
+await
+flushAsyncEvents
+(
+)
+;
+/
+/
+At
+this
+point
+the
+async
+iterator
+has
+a
+read
+request
+in
+the
+stream
+'
+s
+queue
+for
+its
+pending
+next
+(
+)
+promise
+.
+/
+/
+Closing
+the
+stream
+now
+causes
+two
+things
+to
+happen
+*
+synchronously
+*
+:
+/
+/
+1
+.
+ReadableStreamClose
+resolves
+reader
+.
+[
+[
+closedPromise
+]
+]
+with
+undefined
+.
+/
+/
+2
+.
+ReadableStreamClose
+calls
+the
+read
+request
+'
+s
+close
+steps
+which
+calls
+ReadableStreamReaderGenericRelease
+/
+/
+which
+replaces
+reader
+.
+[
+[
+closedPromise
+]
+]
+with
+a
+rejected
+promise
+.
+c
+.
+close
+(
+)
+;
+}
+}
+)
+;
+const
+chunks
+=
+[
+]
+;
+for
+await
+(
+const
+chunk
+of
+rs
+)
+{
+chunks
+.
+push
+(
+chunk
+)
+;
+}
+assert_array_equals
+(
+chunks
+[
+'
+a
+'
+'
+b
+'
+'
+c
+'
+]
+)
+;
+}
+'
+close
+(
+)
+while
+next
+(
+)
+is
+pending
+'
+)
+;