'If C{showAttributes} is set to a sequence of strings, C{__str__}
renders using those by looking them up as attributes on the object.'

def test_sequenceOfStrings(self):

    class Foo(util.FancyStrMixin, ):
        showAttributes = ('first', 'second')
        first = 1
        second = 'hello'
    self.assertEqual(str(Foo()), "<Foo    first=1    second='hello'>")
