allow to receive with a hash of mappings, similar to double(:name, hash)

[rosenfeld]

Currently one can use a shorthand version of double which is very useful, as in:

user = double(:user, id: 1, username: 'admin')

It would be useful to extend this feature when stubbing existing objects as in:

allow(controller).to receive(:authenticate_user!, current_user: user, ...)

The idea is to extract latest argument if it is a hash. In that case, the values will be the return value for the methods as the key names.

For the other arguments, just stubs them as in:

allow(controller).to receive :authenticate_user!

I'd much prefer this style for lots of my stubbings...

[myronmarston]

This is a duplicate of #368. Closing so we can keep the discussion there, in one place.