8   const rs = new ReadableStream();  constant
11   assert_false(rs.locked, 'sanity check: the ReadableStream must not start locked');
14   rs.pipeTo(ws);
16   assert_true(rs.locked, 'the ReadableStream must become locked');
23   const rs = new ReadableStream({  constant
30   return rs.pipeTo(ws).then(() => {
31     assert_false(rs.locked, 'the ReadableStream must become unlocked');
48   const rs = new ReadableStream();  constant
51   return methodRejects(t, ReadableStream.prototype, 'pipeTo', rs, [fakeWS]);
57   const rs = new ReadableStream();  constant
60   rs.getReader();
62   assert_true(rs.locked, 'sanity check: the ReadableStream starts locked');
65   return promise_rejects_js(t, TypeError, rs.pipeTo(ws)).then(() => {
73   const rs = new ReadableStream();  constant
78   assert_false(rs.locked, 'sanity check: the ReadableStream does not start locked');
81   return promise_rejects_js(t, TypeError, rs.pipeTo(ws)).then(() => {
82     assert_false(rs.locked, 'the ReadableStream must still be unlocked');
91   const rs = new ReadableStream({  constant
110   return rs.pipeTo(ws).then(() => {
121       rs.getReader().closed,
133   const rs = recordingReadableStream({  constant
141   const pipePromise = rs.pipeTo(ws).then(() => {
157     const rs = new ReadableStream({  constant
163     return rs.pipeTo(new WritableStream(), { preventAbort }).then(
173     const rs = new ReadableStream({  constant
185     return rs.pipeTo(ws, { preventCancel }).then(
193   const rs = new ReadableStream();  constant
195   return promise_rejects_js(t, TypeError, rs.pipeTo(ws, {
203   const rs = new ReadableStream({  constant
210   return rs.pipeTo(ws, null);