shouldbe 0.1.2

Requirements

• forbiddenfruit

• a version of python with which forbidden fruit will work (must implement the CTypes/CPython Python API)

• Python 2.7 or 3.3 (it may work with other versions, such as other 3.x versions, but it has not been tested with these versions)

Assertions

See ASSERTIONS.rst

Example

>>> import should_be.all
>>> class Cheese(object):
...     crackers = 3
...
>>> swiss = Cheese()
>>> swiss.crackers.should_be(4)
AssertionError: swiss.crackers should have been 4, but was 3

Installation

The easy way

$ sudo pip install https://github.com/DirectXMan12/should_be.git#egg=ShouldBe

The slightly-less-easy way

$ git clone https://github.com/DirectXMan12/should_be.git
$ cd should_be
$ ./setup.py build
$ sudo ./setup.py install

Extending

Writing your own assertions is fairly easy. There are two core parts of ShouldBe: BaseMixin and should_follow.

All assertions should be placed in classes that inherit from BaseMixin. BaseMixin provides the basic utilities for extending built-in objects with your assertions.

The class which holds your assertions should have a class variable called target_class. This is the class on which your assertions will be run. By default, this is set to object. If you wish to have your assertions run on object, there are a few additional considerations to make (see warning below).

Then, assertions should be defined as instance methods. Each method should call self.should_follow one or more times. Think of should_follow as assertTrue on steroids. It has the following signature: should_follow(self, assertion, msg=None, **kwargs). Obviously, assertion is an expression which, when False, causes should_follow to raise an AssertionError. So far, pretty normal. msg is where things get interesting. msg should be a new-style Python format string which contains only named substitutions. By default, should_follow will pass the txt and self keys to the format method, in addition to any keyword arguments passed to should_follow. self is, obviously, the current object. txt is the code that represents the current object. For instance, if we wrote (3).should_be(4), txt would be ‘(3)’. If we wrote cheese.variety.should_be('cheddar'), txt would be ‘cheese.variety’.

Once all of your assertions are written, you can simply write MyAssertionMixin.mix() to load your assertions. A setuptools hook is on the way for autoloading custom assertion mixins with import should_be.all.