Implement Robot Simulator

config.json

@@ -22,6 +22,7 @@
     "roman-numerals",
     "hexadecimal",
     "grade-school",
+    "robot-simulator",
     "queen-attack",
     "sublist",
     "allergies",

exercises/robot-simulator/Cargo.toml

@@ -0,0 +1,3 @@
+[package]
+name = "robot-simulator"
+version = "0.0.0"

exercises/robot-simulator/example.rs

@@ -0,0 +1,101 @@
+#[derive(PartialEq, Debug, Copy, Clone)]
+pub enum Direction {
+    North,
+    East,
+    South,
+    West,
+}
+
+impl Direction {
+    pub fn previous_clockwise(&self) -> Self {
+        match *self {
+            Direction::North => Direction::West,
+            Direction::East => Direction::North,
+            Direction::South => Direction::East,
+            Direction::West => Direction::South,
+        }
+    }
+
+    pub fn next_clockwise(&self) -> Self {
+        match *self {
+            Direction::North => Direction::East,
+            Direction::East => Direction::South,
+            Direction::South => Direction::West,
+            Direction::West => Direction::North,
+        }
+    }
+}
+
+#[derive(Clone, Copy)]
+struct Position {
+    x: i32,
+    y: i32,
+}
+
+impl Position {
+    fn new(x: i32, y: i32) -> Self {
+        Position { x: x, y: y }
+    }
+
+    fn advance(&self, direction: &Direction) -> Self {
+        match *direction {
+            Direction::North => Self::new(self.x, self.y + 1),
+            Direction::South => Self::new(self.x, self.y - 1),
+            Direction::East => Self::new(self.x + 1, self.y),
+            Direction::West => Self::new(self.x - 1, self.y),
+        }
+    }
+}
+
+#[derive(Clone)]
+pub struct Robot {
+    position: Position,
+    direction: Direction,
+}
+
+impl Robot {
+    pub fn new(x: i32, y: i32, d: Direction) -> Self {
+        Robot::build(Position::new(x, y), d)
+    }
+
+    fn build(position: Position, direction: Direction) -> Self {
+        Robot {
+            position: position,
+            direction: direction,
+        }
+    }
+
+    pub fn turn_right(&self) -> Self {
+        Self::build(self.position, self.direction.next_clockwise())
+    }
+
+    pub fn turn_left(&self) -> Self {
+        Self::build(self.position, self.direction.previous_clockwise())
+    }
+
+    pub fn advance(&self) -> Self {
+        Self::build(self.position.advance(&self.direction), self.direction)
+    }
+
+    pub fn instructions(&self, instructions: &str) -> Self {
+        instructions.chars().fold(self.clone(),
+                                  |robot, instruction| robot.execute(instruction))
+    }
+
+    pub fn position(&self) -> (i32, i32) {
+        (self.position.x, self.position.y)
+    }
+
+    pub fn direction(&self) -> &Direction {
+        &self.direction
+    }
+
+    fn execute(self, command: char) -> Self {
+        match command {
+            'R' => self.turn_right(),
+            'L' => self.turn_left(),
+            'A' => self.advance(),
+            _ => self,
+        }
+    }
+}

exercises/robot-simulator/src/lib.rs

@@ -0,0 +1,44 @@
+// The code below is a stub. Just enough to satisfy the compiler.
+// In order to pass the tests you can add-to or change any of this code.
+
+#[derive(PartialEq, Debug)]
+pub enum Direction {
+    North,
+    East,
+    South,
+    West,
+}
+
+pub struct Robot;
+
+impl Robot {
+    #[allow(unused_variables)]
+    pub fn new(x: isize, y: isize, d: Direction) -> Self {
+        unimplemented!()
+    }
+
+    pub fn turn_right(self) -> Self {
+        unimplemented!()
+    }
+
+    pub fn turn_left(self) -> Self {
+        unimplemented!()
+    }
+
+    pub fn advance(self) -> Self {
+        unimplemented!()
+    }
+
+    #[allow(unused_variables)]
+    pub fn instructions(self, instructions: &str) -> Self {
+        unimplemented!()
+    }
+
+    pub fn position(&self) -> (isize, isize) {
+        unimplemented!()
+    }
+
+    pub fn direction(&self) -> &Direction {
+        unimplemented!()
+    }
+}

exercises/robot-simulator/tests/robot-simulator.rs

@@ -0,0 +1,147 @@
+extern crate robot_simulator;
+
+use robot_simulator::*;
+
+#[test]
+fn robots_are_created_with_position_and_direction() {
+    let robot = Robot::new(0, 0, Direction::North);
+    assert_eq!((0, 0), robot.position());
+    assert_eq!(&Direction::North, robot.direction());
+}
+
+#[test]
+#[ignore]
+fn positions_can_be_negative() {
+    let robot = Robot::new(-1, -1, Direction::South);
+    assert_eq!((-1, -1), robot.position());
+    assert_eq!(&Direction::South, robot.direction());
+}
+
+#[test]
+#[ignore]
+fn turning_right_does_not_change_position() {
+    let robot = Robot::new(0, 0, Direction::North).turn_right();
+    assert_eq!((0, 0), robot.position());
+}
+
+#[test]
+#[ignore]
+fn turning_right_from_north_points_the_robot_east() {
+    let robot = Robot::new(0, 0, Direction::North).turn_right();
+    assert_eq!(&Direction::East, robot.direction());
+}
+
+#[test]
+#[ignore]
+fn turning_right_from_east_points_the_robot_south() {
+    let robot = Robot::new(0, 0, Direction::East).turn_right();
+    assert_eq!(&Direction::South, robot.direction());
+}
+
+#[test]
+#[ignore]
+fn turning_right_from_south_points_the_robot_west() {
+    let robot = Robot::new(0, 0, Direction::South).turn_right();
+    assert_eq!(&Direction::West, robot.direction());
+}
+
+#[test]
+#[ignore]
+fn turning_right_from_west_points_the_robot_north() {
+    let robot = Robot::new(0, 0, Direction::West).turn_right();
+    assert_eq!(&Direction::North, robot.direction());
+}
+
+#[test]
+#[ignore]
+fn turning_left_does_not_change_position() {
+    let robot = Robot::new(0, 0, Direction::North).turn_left();
+    assert_eq!((0, 0), robot.position());
+}
+
+#[test]
+#[ignore]
+fn turning_left_from_north_points_the_robot_west() {
+    let robot = Robot::new(0, 0, Direction::North).turn_left();
+    assert_eq!(&Direction::West, robot.direction());
+}
+
+#[test]
+#[ignore]
+fn turning_left_from_west_points_the_robot_south() {
+    let robot = Robot::new(0, 0, Direction::West).turn_left();
+    assert_eq!(&Direction::South, robot.direction());
+}
+
+#[test]
+#[ignore]
+fn turning_left_from_south_points_the_robot_east() {
+    let robot = Robot::new(0, 0, Direction::South).turn_left();
+    assert_eq!(&Direction::East, robot.direction());
+}
+
+#[test]
+#[ignore]
+fn turning_left_from_east_points_the_robot_north() {
+    let robot = Robot::new(0, 0, Direction::East).turn_left();
+    assert_eq!(&Direction::North, robot.direction());
+}
+
+#[test]
+#[ignore]
+fn advance_does_not_change_the_direction() {
+    let robot = Robot::new(0, 0, Direction::North).advance();
+    assert_eq!(&Direction::North, robot.direction());
+}
+
+#[test]
+#[ignore]
+fn advance_increases_the_y_coordinate_by_one_when_facing_north() {
+    let robot = Robot::new(0, 0, Direction::North).advance();
+    assert_eq!((0, 1), robot.position());
+}
+
+#[test]
+#[ignore]
+fn advance_decreases_the_y_coordinate_by_one_when_facing_south() {
+    let robot = Robot::new(0, 0, Direction::South).advance();
+    assert_eq!((0, -1), robot.position());
+}
+
+#[test]
+#[ignore]
+fn advance_increases_the_x_coordinate_by_one_when_facing_east() {
+    let robot = Robot::new(0, 0, Direction::East).advance();
+    assert_eq!((1, 0), robot.position());
+}
+
+#[test]
+#[ignore]
+fn advance_decreases_the_x_coordinate_by_one_when_facing_west() {
+    let robot = Robot::new(0, 0, Direction::West).advance();
+    assert_eq!((-1, 0), robot.position());
+}
+
+#[test]
+#[ignore]
+fn follow_instructions_to_move_west_and_north() {
+    let robot = Robot::new(0, 0, Direction::North).instructions("LAAARALA");
+    assert_eq!((-4, 1), robot.position());
+    assert_eq!(&Direction::West, robot.direction());
+}
+
+#[test]
+#[ignore]
+fn follow_instructions_to_move_west_and_south() {
+    let robot = Robot::new(2, -7, Direction::East).instructions("RRAAAAALA");
+    assert_eq!((-3, -8), robot.position());
+    assert_eq!(&Direction::South, robot.direction());
+}
+
+#[test]
+#[ignore]
+fn follow_instructions_to_move_east_and_north() {
+    let robot = Robot::new(8, 4, Direction::South).instructions("LAAARRRALLLL");
+    assert_eq!((11, 5), robot.position());
+    assert_eq!(&Direction::North, robot.direction());
+}