Add test for enums in ron

Signed-off-by: Matthias Beyer <mail@beyermatthias.de>

Author: matthiasbeyer

tests/ron_enum.rs

@@ -0,0 +1,35 @@
+use config::{Config, File, FileFormat};
+use serde_derive::Deserialize;
+
+#[derive(Debug, Deserialize)]
+#[serde(untagged)]
+enum A {
+    VariantA { port: u16 },
+}
+
+#[derive(Debug, Deserialize)]
+struct Settings {
+    a: A,
+}
+
+#[test]
+fn test_ron_enum() {
+    let c = Config::builder()
+        .add_source(File::from_str(
+            r#"
+            (
+                a: VariantA ( port: 5000 )
+            )
+            "#,
+            FileFormat::Ron,
+        ))
+        .build()
+        .unwrap();
+
+    // Deserialize the entire file as single struct
+    let s = c.try_deserialize::<Settings>();
+    assert!(s.is_ok(), "Not Ok(_): {}", s.unwrap_err());
+    let s = s.unwrap();
+    let A::VariantA { port } = s.a;
+    assert_eq!(port, 5000);
+}