def test_full_volume(self):
        """Full volume is well-behaved"""
        full = volume.FullVolume()
        test = 0.1
        assert_equal(full(test), True)
        assert_equal((full & volA)(test), True)
        assert_equal((volA & full)(test), True)
        assert_equal((full | volA)(test), True)
        assert_equal((volA | full)(test), True)
        # assert_is: logical combos with full should return same obj
        assert_is((full & volA), volA)
        assert_is((volA & full), volA)
        assert_is((full | volA), full)
        assert_is((volA | full), full)
        assert_equal((volA - full), volume.EmptyVolume())
        assert_equal((full - volA), ~ volA)
        assert_equal((full ^ volA), ~ volA)
        assert_equal((volA ^ full), ~ volA)
        assert_equal((volA | full).__str__(), "all")
        assert_equal((~ full).__str__(), "empty")