Add test for serde renamed member

Signed-off-by: Matthias Beyer <[email protected]>

tests/rename.rs

@@ -0,0 +1,23 @@
+#[test]
+fn test_rename_attr() {
+    use config::{Config, File, FileFormat};
+
+    #[allow(unused)]
+    #[derive(serde::Deserialize, Debug)]
+    struct MyConfig {
+        #[serde(rename = "FooBar")]
+        foo_bar: String,
+    }
+
+    const MY_CONFIG: &str = r#"{
+        "FooBar": "Hello, world!"
+    }"#;
+
+    let cfg = Config::builder()
+        .add_source(File::from_str(MY_CONFIG, FileFormat::Json))
+        .build()
+        .unwrap();
+
+    let desered: Result<MyConfig, _> = cfg.try_deserialize();
+    assert!(desered.is_ok(), "Not Ok(_): {}", desered.unwrap_err());
+}