provider provides (all puns intended) a more compact way to do what
provider + inject used to. It infers the interface to provide based on
decorated method's return type annotations therefore cooperating nicely
with type hints[1] and tools that use them.
Some source files are no longer fed to py.test because they contain
Python 3+ only syntax.
[1] https://docs.python.org/3/library/typing.html
Jakub Stasiak