first tuple test

tuples/src/lib.rs

@@ -0,0 +1,47 @@
+type PointVector = (f32, f32, f32, f32);
+
+fn tuple_x(tuple: PointVector) -> f32 {
+    tuple.0
+}
+
+fn tuple_y(tuple: PointVector) -> f32 {
+    tuple.1
+}
+
+fn tuple_z(tuple: PointVector) -> f32 {
+    tuple.2
+}
+
+fn tuple_is_point(tuple: PointVector) -> bool {
+    tuple.3 == 1.0
+}
+fn tuple_is_vector(tuple: PointVector) -> bool {
+    tuple.3 == 0.0
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn get_point() {
+        let tuple = (4.3, -4.2, 3.1, 1.0);
+
+        assert_eq!( 4.3,  tuple_x(tuple));
+        assert_eq!(-4.2,  tuple_y(tuple));
+        assert_eq!( 3.1,  tuple_z(tuple));
+        assert_eq!(true,  tuple_is_point(tuple));
+        assert_eq!(false, tuple_is_vector(tuple));
+    }
+
+    #[test]
+    fn get_vector() {
+        let tuple = (4.3, -4.2, 3.1, 0.0);
+
+        assert_eq!( 4.3,  tuple_x(tuple));
+        assert_eq!(-4.2,  tuple_y(tuple));
+        assert_eq!( 3.1,  tuple_z(tuple));
+        assert_eq!(false, tuple_is_point(tuple));
+        assert_eq!(true,  tuple_is_vector(tuple));
+    }
+}