interface-mixins 0.0.4

Interfaces for Python

Warning

This project is archived and is no longer maintained. No further updates or releases will be made. For defining interfaces in Python, we recommend using Python’s built-in abc (Abstract Base Classes) module, typing.Protocol (for structural subtyping/duck typing), or zope.interface.

To create an Interface, pass it an interface name and a list of method names. A class will be created which raises NotImplementedError for each of the specified method names:

AnInterface = Interface('AnInterface', [
    'some',
    'methods',
    'the',
    'interface',
    'should',
    'have'
])

To use this interface, simply inherit from it:

class AClass(AnInterface):
    pass

We also provide a way to create abstract test cases to help test objects against the interface:

AbstractTestAnInterface = AbstractInterfaceTest('AbstractTestAnInterface', [
    'some',
    'methods',
    'the',
    'interface',
    'should',
    'have'
])

These tests can be used by creating TestCases which inherit from from the abstract test. This makes sure each method is implemented in AClass:

from unittest import TestCase

class TestAClass(AbstractTestAnInterface, TestCase):
    def setUp(self):
        self.obj = AClass()

It is also possible to create both the Interface and the AbstractInterfaceTest at the same time. Also, you can create multiple interfaces using the following idiom [1]:

interfaces = {
    'AnInterface': [
        'some',
        'methods',
        'the',
        'interface',
        'should',
        'have'
    ],
    'AnotherInterface': [
        'different',
        'methods'
    ]
}

for interface_name, methods in interfaces.iteritems():
    interface_name += 'Interface'
    globals()[interface_name] = Interface(interface_name, methods)
    test_name = 'AbstractTest' + interface_name
    globals()[test_name] = AbstractInterfaceTest(test_name, methods)

[1]

This isn’t very idiomatic Python. The use globals is ugly. This is just an idiom for using this library. I’m not sure I like it.