// [dependencies]
// serde = {version = "1", features = ["derive"]}
// serde_json = "1"

use serde;
use serde_json;

#[derive(serde::Deserialize)]
pub struct Foo {
    pub bar: i64,
}

#[derive(serde::Deserialize, Default)]
pub struct NoContent {}

#[derive(serde::Deserialize)]
#[serde(tag = "tag", content = "content")]
#[serde(rename_all = "snake_case")]
pub enum Data {
    WithContent(Foo),
    WithOptContent(Option<NoContent>),
    // There is no way to make this work.
    WithoutContent(#[serde(default)] NoContent),
}

#[test]
fn deserialize() {
    let things = vec![
        r#"{"tag":"with_content", "content": { "bar": 10}}"#, // This works fine
        r#"{"tag":"with_opt_content"}"#, // This works because the content is wrapped with an Option
        r#"{"tag":"without_content" }"#, // This fails
    ];
    for i in things {
        serde_json::from_str::<Data>(i).unwrap_or_else(|_| panic!("failed on {:?}", i));
    }
}