Add more unit tests for Ray

src/lib.rs

@@ -27,17 +27,33 @@ extern crate quickcheck;
 extern crate quickcheck_macros;
 mod tests {
     use super::*;
-    use quickcheck::{Arbitrary,Gen};
+    use quickcheck::{Arbitrary, Gen};
-    impl<T:Arbitrary+RealField> Arbitrary for Ray<T> {
+    impl<T: Arbitrary + RealField> Arbitrary for Ray<T> {
-        fn arbitrary<G:Gen>(g: &mut G) -> Ray<T> {
+        fn arbitrary<G: Gen>(g: &mut G) -> Ray<T> {
             let origin = <Vector3<T> as Arbitrary>::arbitrary(g);
             let direction = <Vector3<T> as Arbitrary>::arbitrary(g);
-            return Ray{origin, direction}
+            return Ray::new(origin, direction);
         }
     }
 
     #[quickcheck]
-    fn test_t0_is_origin(ray:Ray<f64>) -> bool {
+    fn t0_is_origin(ray: Ray<f64>) -> bool {
         ray.point_at(0.0) == ray.origin
     }
+
+    #[quickcheck]
+    fn t1_is_origin_plus_direction(ray: Ray<f64>) -> bool {
+        ray.point_at(1.0) == ray.origin + ray.direction
+    }
+
+    #[quickcheck]
+    fn points_are_colinear(ray: Ray<f64>, t1: f64, t2: f64, t3: f64) -> bool {
+        let p1 = ray.point_at(t1);
+        let p2 = ray.point_at(t2);
+        let p3 = ray.point_at(t3);
+        let epsilon = [t1, t2, t3, ray.origin[0], ray.origin[1], ray.origin[2]]
+            .iter()
+            .fold(0.0, |a, &b| a.max(b.abs())) * std::f64::EPSILON * 128.0;
+        (p2 - p1).cross(&(p3 - p2)).norm() < epsilon
+    }
 }