# Copyright (c) 2017 Mark D. Hill and David A. Wood
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#
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# 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
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# this software without specific prior written permission.
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# Authors: Sean Wilson

import copy
import traceback

import helper
import log

class SkipException(Exception):
    def __init__(self, fixture, testitem):
        self.fixture = fixture
        self.testitem = testitem

        self.msg = 'Fixture "%s" raised SkipException for "%s".' % (
               fixture.name, testitem.name
        )
        super(SkipException, self).__init__(self.msg)


class Fixture(object):
    '''
    Base Class for a test Fixture.

    Fixtures are items which possibly require setup and/or tearing down after
    a TestCase, TestSuite, or the Library has completed.

    Fixtures are the prefered method of carrying incremental results or
    variables between TestCases in TestSuites. (Rather than using globals.)
    Using fixtures rather than globals ensures that state will be maintained
    when executing tests in parallel.

    .. note:: In order for Fixtures to be enumerated by the test system this
        class' :code:`__new__` method must be called.
    '''
    collector = helper.InstanceCollector()

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

    def __init__(self, name=None, **kwargs):
        if name is None:
            name = self.__class__.__name__
        self.name = name
        self._is_global = False

    def skip(self, testitem):
        raise SkipException(self.name, testitem.metadata)

    def init(self, *args, **kwargs):
        pass

    def setup(self, testitem):
        pass

    def teardown(self, testitem):
        pass

    def skip_cleanup(self):
        '''
        If this method is called, then we should make sure that nothing is
        done when the teardown() function is called.
        '''
        pass

    def set_global(self):
        self._is_global = True

    def is_global(self):
        return self._is_global