'When merging group_access on a block, the resulting group IDs for each
partition is the intersection of the group IDs defined for that
partition across all ancestor blocks (including this one).'

@ddt.data(*PARENT_CHILD_PAIRS)
@ddt.unpack
def test_intersecting_groups(self, parent, child):

    parent_block = getattr(self, parent)
    child_block = getattr(self, child)
    self.set_group_access(parent_block, {self.PARTITION_1: [self.PARTITION_1_GROUP_1, self.PARTITION_1_GROUP_2]})
    self.set_group_access(child_block, {self.PARTITION_1: [self.PARTITION_1_GROUP_2]})
    self.verify_group_access(parent_block, {self.PARTITION_1: [self.PARTITION_1_GROUP_1, self.PARTITION_1_GROUP_2]})
    self.verify_group_access(child_block, {self.PARTITION_1: [self.PARTITION_1_GROUP_2]})
