simplify code and make setup & teardown processes more reliable
add testing.Stack tools which stacks promise-returning functions
around the actual promise-returning function to execute (the test case
itself).
testing.Stack returns an object with 3 methods, ``push([setup][,
teardown])``, ``unshift([setup][, teardown])`` and ``execute(fn,
*args)``. ``push`` and ``unshift`` create a new stack with the
provided setup and teardown added respectively at the top and bottom
of the stack.
``execute`` will walk the stack from bottom to top executing ``setup``
handlers (and waiting on their result), if all setup handlers execute
without failure the ``fn`` callback gets executed (and waited on) then
*all* ``teardown`` handlers are executed from top to bottom:
| setup
| setup
| setup
| setup
| fn
| teardown
| teardown
| teardown
V teardown
If a ``setup`` handler fails (the promise is rejected), teardowns will
start executing *from the previous level* (so the ``teardown``
matching the failed ``setup`` will *not* be run), but all
``teardowns`` below that will be run regardless, even if one fails the
next one will still be executed.
The stack will either ultimately return a promise rejection using the
*first* rejection it got (a rejection may be cascading, so the
rejection of a setup may also lead to or be linked to a teardown being
rejected later), or will return the resolution from ``fn``.
If ``execute`` is passed further arguments, those arguments will in
turn be forwarded to ``fn`` as well as all ``setup`` and ``teardown``
handlers.
bzr revid: xmo@openerp.com-20121116071712-zuld957icellezum
Géry Debongnie