ext/testlib/test_util.py

# Copyright (c) 2017 Mark D. Hill and David A. Wood
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met: redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer;
# redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution;
# neither the name of the copyright holders nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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# Authors: Sean Wilson

import functools

import testlib.helper as helper
import testlib.runner as runner_mod

class TestingException(Exception):
    '''Common ancestor for manual Testing Exceptions.'''
class TestFailException(TestingException):
    '''Signals that a test has failed.'''
class TestSkipException(TestingException):
    '''Signals that a test has been skipped.'''

def fail(message):
    '''Cause the current test to fail with the given message.'''
    raise TestFailException(message)

def skip(message):
    '''Cause the current test to skip with the given message.'''
    raise TestSkipException(message)

class TestCase(object):
    '''
    Base class for all tests.

    ..note::
        The :func:`__new__` method enables collection of test cases, it must
        be called in order for test cases to be collected.
    '''
    fixtures = []

    # TODO, remove explicit dependency. Use the loader to set the
    # default runner
    runner = runner_mod.TestRunner
    collector = helper.InstanceCollector()

    def __new__(cls, *args, **kwargs):
        obj = super(TestCase, cls).__new__(cls)
        TestCase.collector.collect(obj)
        return obj

    def __init__(self, name=None, fixtures=tuple(), **kwargs):
        self.fixtures = self.fixtures + list(fixtures)
        if name is None:
            name = self.__class__.__name__
        self.name = name

class TestFunction(TestCase):
    '''
    TestCase implementation which uses a callable object as a test.
    '''
    def __init__(self, function, name=None, **kwargs):
        self.test_function = function
        if name is None:
            name = function.__name__
        TestCase.__init__(self, name=name, **kwargs)

    def test(self, *args, **kwargs):
        self.test_function(*args, **kwargs)

# TODO Change the decorator to make this easier to create copy tests.
# Good way to do so might be return by reference.
def testfunction(function=None, name=None, fixtures=tuple()):
    '''
    A decorator used to wrap a function as a TestFunction.
    '''
    def testfunctiondecorator(function):
        '''Decorator used to mark a function as a test case.'''
        kwargs = {}
        if name is not None:
            kwargs['name'] = name
        if fixtures is not None:
            kwargs['fixtures'] = fixtures
        TestFunction(function, **kwargs)
        return function
    if function is not None:
        return testfunctiondecorator(function)
    else:
        return testfunctiondecorator