
FAIL Closing must be propagated backward: starts closed; preventCancel omitted; fulfilled cancel promise ws.getWriter is not a function. (In 'ws.getWriter()', 'ws.getWriter' is undefined)
FAIL Closing must be propagated backward: starts closed; preventCancel omitted; rejected cancel promise ws.getWriter is not a function. (In 'ws.getWriter()', 'ws.getWriter' is undefined)
FAIL Closing must be propagated backward: starts closed; preventCancel = undefined (falsy); fulfilled cancel promise ws.getWriter is not a function. (In 'ws.getWriter()', 'ws.getWriter' is undefined)
FAIL Closing must be propagated backward: starts closed; preventCancel = null (falsy); fulfilled cancel promise ws.getWriter is not a function. (In 'ws.getWriter()', 'ws.getWriter' is undefined)
FAIL Closing must be propagated backward: starts closed; preventCancel = false (falsy); fulfilled cancel promise ws.getWriter is not a function. (In 'ws.getWriter()', 'ws.getWriter' is undefined)
FAIL Closing must be propagated backward: starts closed; preventCancel = 0 (falsy); fulfilled cancel promise ws.getWriter is not a function. (In 'ws.getWriter()', 'ws.getWriter' is undefined)
FAIL Closing must be propagated backward: starts closed; preventCancel = -0 (falsy); fulfilled cancel promise ws.getWriter is not a function. (In 'ws.getWriter()', 'ws.getWriter' is undefined)
FAIL Closing must be propagated backward: starts closed; preventCancel = NaN (falsy); fulfilled cancel promise ws.getWriter is not a function. (In 'ws.getWriter()', 'ws.getWriter' is undefined)
FAIL Closing must be propagated backward: starts closed; preventCancel =  (falsy); fulfilled cancel promise ws.getWriter is not a function. (In 'ws.getWriter()', 'ws.getWriter' is undefined)
FAIL Closing must be propagated backward: starts closed; preventCancel = true (truthy) ws.getWriter is not a function. (In 'ws.getWriter()', 'ws.getWriter' is undefined)
FAIL Closing must be propagated backward: starts closed; preventCancel = a (truthy) ws.getWriter is not a function. (In 'ws.getWriter()', 'ws.getWriter' is undefined)
FAIL Closing must be propagated backward: starts closed; preventCancel = 1 (truthy) ws.getWriter is not a function. (In 'ws.getWriter()', 'ws.getWriter' is undefined)
FAIL Closing must be propagated backward: starts closed; preventCancel = Symbol() (truthy) ws.getWriter is not a function. (In 'ws.getWriter()', 'ws.getWriter' is undefined)
FAIL Closing must be propagated backward: starts closed; preventCancel = [object Object] (truthy) ws.getWriter is not a function. (In 'ws.getWriter()', 'ws.getWriter' is undefined)
FAIL Closing must be propagated backward: starts closed; preventCancel = true, preventAbort = true ws.getWriter is not a function. (In 'ws.getWriter()', 'ws.getWriter' is undefined)
FAIL Closing must be propagated backward: starts closed; preventCancel = true, preventAbort = true, preventClose = true ws.getWriter is not a function. (In 'ws.getWriter()', 'ws.getWriter' is undefined)