Add #562 as a test

Co-authored-by: porkbrain <git@porkbrain.com>

tests/562_flatten.rs

@@ -0,0 +1,54 @@
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
+struct SomeCollection {
+    inner: Vec<SomeItem>,
+}
+
+#[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
+struct SomeItem {
+    #[serde(flatten)]
+    foo: Foo,
+    #[serde(flatten)]
+    bar: Bar,
+}
+
+#[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
+struct Bar {
+    name: String,
+    some_enum: Option<SomeEnum>,
+}
+
+#[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
+struct Foo {
+    something: String,
+}
+
+#[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
+enum SomeEnum {
+    A,
+    B,
+}
+
+#[test]
+fn roundtrip() {
+    let scene = SomeCollection {
+        inner: vec![SomeItem {
+            foo: Foo {
+                something: "something".to_string(),
+            },
+            bar: Bar {
+                name: "name".to_string(),
+                some_enum: Some(SomeEnum::A),
+            },
+        }],
+    };
+
+    let ron = ron::ser::to_string(&scene).unwrap();
+    let de: SomeCollection = ron::de::from_str(&ron).unwrap();
+    assert_eq!(de, scene);
+
+    let ron = ron::ser::to_string_pretty(&scene, Default::default()).unwrap();
+    let _deser_scene: SomeCollection = ron::de::from_str(&ron).unwrap();
+    assert_eq!(de, scene);
+}