PASS Underlying sink: throwing start getter
PASS Underlying sink: throwing start method
FAIL Underlying sink: throwing write getter a unique string
FAIL Underlying sink: throwing write method ws.write is not a function. (In 'ws.write('a')', 'ws.write' is undefined)
FAIL Underlying sink: throwing abort getter a unique string
FAIL Underlying sink: throwing abort method undefined is not an object (evaluating 'ws.closed.then')
FAIL Underlying sink: throwing close getter a unique string
PASS Underlying sink: throwing close method