assertSer = (val, body, slots, message) =>
    t.deepEqual(serialize(val), { body, slots }, message)
A test case to illustrate each of the encodings
 * `!` - escaped string
 * `+` - non-negative bigint
 * `-` - negative bigint
 * `#` - manifest constant
 * `%` - symbol
 * `$` - remotable
 * `&` - promise