Add serde serialization test

Cargo.toml

@@ -40,3 +40,4 @@ serde_macros = { version = "0.7", optional = true }
 
 [dev-dependencies]
 glium = "0.14.0"
+serde_json = "0.7"

tests/transform.rs

@@ -16,6 +16,9 @@
 
 extern crate cgmath;
 
+#[cfg(feature = "eders")]
+extern crate serde_json;
+
 use cgmath::*;
 
 #[test]
@@ -23,8 +26,8 @@ fn test_invert() {
     let v = Vector3::new(1.0f64, 2.0, 3.0);
     let t = Decomposed {
         scale: 1.5f64,
-        rot: Quaternion::new(0.5f64,0.5,0.5,0.5),
-        disp: Vector3::new(6.0f64,-7.0,8.0)
+        rot: Quaternion::new(0.5f64, 0.5, 0.5, 0.5),
+        disp: Vector3::new(6.0f64, -7.0, 8.0),
     };
     let ti = t.inverse_transform().expect("Expected successful inversion");
     let vt = t.transform_vector(v);
@@ -41,3 +44,18 @@ fn test_look_at() {
     let view_point = Point3::new(0.0f64, 1.0, 5.0);
     assert!(t.transform_point(point).approx_eq(&view_point));
 }
+
+#[cfg(feature = "eders")]
+#[test]
+fn test_serialize() {
+    let t = Decomposed {
+        scale: 1.5f64,
+        rot: Quaternion::new(0.5f64, 0.5, 0.5, 0.5),
+        disp: Vector3::new(6.0f64, -7.0, 8.0),
+    };
+
+    let serialized = serde_json::to_string(&t).unwrap();
+    let deserialized: Decomposed<Vector3<f64>, Quaternion<f64>> = serde_json::from_str(&serialized).unwrap();
+
+    assert!(t.approx_eq(&deserialized));
+}