sources for test_viewtype.py [rev. unknown]

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from py.__.magic.viewtype import View

def test_class_dispatch():

    ### Use a custom class hierarchy with existing instances

    class Picklable(View):

        pass

    class Simple(Picklable):

        __view__ = object

        def pickle(self):

            return repr(self.__obj__)

    class Seq(Picklable):

        __view__ = list, tuple, dict

        def pickle(self):

            return ';'.join([Picklable(item).pickle() for item in self.__obj__])

    class Dict(Seq):

        __view__ = dict

        def pickle(self):

            return Seq.pickle(self) + '!' + Seq(self.values()).pickle()

    assert Picklable(123).pickle() == '123'

    assert Picklable([1,[2,3],4]).pickle() == '1;2;3;4'

    assert Picklable({1:2}).pickle() == '1!2'

def test_custom_class_hierarchy():

    ### Use a custom class hierarchy based on attributes of existing instances

    class Operation:

        "Existing class that I don't want to change."

        def __init__(self, opname, *args):

            self.opname = opname

            self.args = args

    existing = [Operation('+', 4, 5),

                Operation('getitem', '', 'join'),

                Operation('setattr', 'x', 'y', 3),

                Operation('-', 12, 1)]

    class PyOp(View):

        def __viewkey__(self):

            return self.opname

        def generate(self):

            return '%s(%s)' % (self.opname, ', '.join(map(repr, self.args)))

    class PyBinaryOp(PyOp):

        __view__ = ('+', '-', '*', '/')

        def generate(self):

            return '%s %s %s' % (self.args[0], self.opname, self.args[1])

    codelines = [PyOp(op).generate() for op in existing]

    assert codelines == ["4 + 5", "getitem('', 'join')", "setattr('x', 'y', 3)", "12 - 1"]