add serde test

Author: moon-stripe

tests/serde.rs

@@ -0,0 +1,22 @@
+extern crate graphql_parser;
+use std::fs::File;
+use std::io::Read;
+
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
+
+use graphql_parser::parse_schema;
+
+#[cfg(feature = "serde")]
+fn serialize<'a, T: Serialize + Deserialize<'a>>(_: T) {}
+
+#[cfg(feature = "serde")]
+#[test]
+fn serializable() {
+    let mut buf = String::with_capacity(1024);
+    let path = format!("tests/schemas/minimal.graphql");
+    let mut f = File::open(path).unwrap();
+    f.read_to_string(&mut buf).unwrap();
+    let ast = parse_schema::<String>(&buf).unwrap().to_owned();
+    serialize(ast);
+}