How sure works
==============

The class ``sure.AssertionBuilder`` creates objects capable of doing
assertions. The AssertionBuilder simply arranges a vast set of possible
assertions that are composed by a ``source`` object and a
``destination`` object.

Every assertion, even implicitly if implicitly like in
``(2 < 3).should.be.true``, is doing a source/destination matching.

Chainability
------------

Some specific assertion methods are chainable, it can be useful for
short assertions like:

.. code:: python

    PERSON = {
      "name": "John",
      "facebook_info": {
        "token": "abcd"
      }
    }

    PERSON.should.have.key("facebook_info").being.a(dict)

Monkey-patching
===============

Lincoln Clarete has written the module [``sure/magic.py``] which I
simply added to sure. The most exciting part of the story is that
Lincoln exposed the code with a super clean API, it's called `forbidden
fruit <http://clarete.github.io/forbiddenfruit/>`__

Why CPython-only ?
------------------

Sure uses the `ctypes <http://docs.python.org/library/ctypes>`__ module
to break in python protections against monkey patching.

Although ctypes might also be available in other implementations such as
`Jython <http://www.jython.org/>`__, only the CPython provide
```ctypes.pythonapi`` <http://docs.python.org/library/ctypes#loading-shared-libraries>`__
the features required by sure.
