generate random Orientation enum

Cargo.toml

@@ -8,3 +8,4 @@ edition = "2018"
 
 [dependencies]
 clap = "2.33.3"
+rand = "0.7.3"

src/robot.rs

@@ -1,5 +1,10 @@
 /// A Robot *aka droid* is represented here.
 /// Each robot must have a unique id.
+use rand::{
+    distributions::{Distribution, Standard},
+    Rng,
+};
+
 pub struct Robot {
     pub id: u32,
     pub o: Orientation,
@@ -42,6 +47,7 @@ impl Robot {
 }
 
 /// Enum to store all possible orientations.
+#[derive(Debug)]
 pub enum Orientation {
     N,
     E,
@@ -49,6 +55,17 @@ pub enum Orientation {
     W,
 }
 
+impl Distribution<Orientation> for Standard {
+    fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Orientation {
+        match rng.gen_range(0, 3) {
+            0 => Orientation::N,
+            1 => Orientation::E,
+            2 => Orientation::S,
+            _ => Orientation::W,
+        }
+    }
+}
+
 /// Struct to store robot position.
 #[derive(PartialEq, Eq, Hash)]
 pub struct Position {
@@ -101,6 +118,17 @@ pub fn print_robots(robot_pool: &Vec<Robot>) {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use std::any::type_name;
+
+    fn type_of<T>(_: T) -> &'static str {
+        type_name::<T>()
+    }
+
+    #[test]
+    fn test_rand_orientation() {
+        let o: Orientation = rand::random();
+        assert_eq!(type_of(o), "dancing_droid::robot::Orientation");
+    }
 
     #[test]
     fn test_new_robot() {