// META: script=/resources/test-only-api.js
// META: script=/serial/resources/common.js
// META: script=resources/automation.js
serial_test(async (t, fake) => {
const {port, fakePort} = await getFakeSerialPort(fake);
await port.open({baudRate: 9600});
assert_true(port.readable instanceof ReadableStream);
const reader = port.readable.getReader();
await promise_rejects_js(t, TypeError, port.close());
reader.releaseLock();
await port.close();
assert_equals(port.readable, null);
}, 'Port cannot be closed while readable is locked');