///|
fn main raise {
  let schema = @schema.parse("[\"int\",\"string\"]")
  let original = @codec.Union(0, @codec.Int(2026))
  let encoded = @codec.encode(schema, original)
  let decoded = @codec.decode(schema, encoded)
  assert_eq(decoded, original)
  println("primitive/union roundtrip: ok")
}