An example of using metaclasses to enable declarative tests.

parser_metatest_example.py

# -*- coding: utf-8 -*-
"""actions.tests -- tests for action commands.

Copyright 2010 David Eyk. All rights reserved.
"""
import re
from django.test import TestCase

from . import base
from . import actions
from . import social
from . import attributes

from things import models as things


class CommandParserMeta(type):
    """Create tests for each command/expected_response pair on the class.
    """
    slug_cp = re.compile(r'[^a-zA-Z_]+')

    def __new__(meta, classname, bases, attrs):
        klass = super(CommandParserMeta, meta).__new__(meta, classname, bases, attrs)
        
        for command, expected_result in klass.command_result:
            command_slug = 'test_%s' % meta.slug_cp.sub('_', command)

            # Build basic parser test
            setattr(klass, command_slug, meta.buildBasicParserTest(command, expected_result))

        return klass

    @staticmethod
    def buildBasicParserTest(command, expected_result):
        def test(self):
            """Can we parse '%s'?
            """ % command
            result = sorted(dict(self.action.parse(command)).iteritems())
            expected = sorted(expected_result.iteritems())
            self.assertEqual(result, expected)
        return test


class CommandParserTest(TestCase):
    __metaclass__ = CommandParserMeta

    action = None

    def setUp(self):
        self.actor = things.Actor.new()

    command_result = ()


class LookParserTest(CommandParserTest):
    action = actions.Look

    command_result = (
        ('look', dict(command='look', target='here')),
        ('l', dict(command='l', target='here')),
        ('look me', dict(command='look', target='me')),
        )


class ExamineParserTest(CommandParserTest):
    action = actions.Examine

    command_result = (
        ('examine', dict(command='examine', target='here')),
        ('ex', dict(command='ex', target='here')),
        ('ex me', dict(command='ex', target='me')),
        )


class DigParserTest(CommandParserTest):
    action = actions.Dig

    command_result = (
        ('@dig Waterfall', dict(command='@dig', target='Waterfall')),
        ('@dig/teleport Waterfall', dict(command='@dig', teleport='teleport', target='Waterfall')),
        ('@dig Waterfall = West', dict(command='@dig', target='Waterfall', 
                                       outgoing_names=['West'])),
        ('@dig Waterfall = West;W', dict(command='@dig', target='Waterfall', 
                                         outgoing_names=['West', 'W'])),
        ('@dig Waterfall = West;W, East;E', dict(command='@dig', target='Waterfall', 
                                                 outgoing_names=['West', 'W'], incoming_names=['East', 'E'])),
        )


class SayParserTest(CommandParserTest):
    action = social.Say

    command_result = (
        ('say Hello, world!', dict(command='say', utterance="Hello, world!")),
        ('"Hello, world!', dict(command='"', utterance="Hello, world!")),
        )


class PoseParserTest(CommandParserTest):
    action = social.Pose

    command_result = (
        ('pose drops his hat', dict(command='pose', action="drops his hat")),
        (':drops his hat', dict(command=':', action="drops his hat")),
        )


class SpacelessPoseParserTest(CommandParserTest):
    action = social.SpacelessPose

    command_result = (
        ("spose 's hat blows away in the wind", dict(command='spose', action="'s hat blows away in the wind")),
        (";'s hat blows away in the wind", dict(command=';', action="'s hat blows away in the wind")),
        )


class SetParserTest(CommandParserTest):
    action = attributes.Set

    command_result = (
        ("@set desc me = Tall, dark, mysterious.", dict(command='@set', attr='desc', target='me', value="Tall, dark, mysterious.")),
        )


class DescParserTest(CommandParserTest):
    action = attributes.Desc

    command_result = (
        ("@desc me = Tall, dark, mysterious.", dict(command='@desc', target='me', desc="Tall, dark, mysterious.")),
        )