rover: use direction when going forward

rover/rover.py

@@ -19,3 +19,13 @@ class Rover(BaseModel):
     pos: Vector = Vector(x=0, y=0)
     planet_size: Vector = Vector(x=100, y=100)
     dir: Direction = Direction.NORTH
+
+    def forward(self):
+        if self.dir == Direction.NORTH:
+            self.pos.y += 1
+        elif self.dir == Direction.SOUTH:
+            self.pos.y -= 1
+        elif self.dir == Direction.EAST:
+            self.pos.x += 1
+        elif self.dir == Direction.WEST:
+            self.pos.x -= 1

rover/test_rover.py

@@ -19,3 +19,44 @@ def test_rover_has_direction():
 def test_rover_default_direction_is_north():
     rov = Rover()
     assert rov.dir == Direction.NORTH
+
+
+def test_rover_can_go_forward_once_going_north():
+    rov = Rover(
+        pos=Vector(x=0, y=0), planet_size=Vector(x=10, y=10), dir=Direction.NORTH
+    )
+    rov.forward()
+    assert rov.pos == Vector(x=0, y=1)
+
+
+def test_rover_can_go_forward_twice_going_north():
+    rov = Rover(
+        pos=Vector(x=0, y=0), planet_size=Vector(x=10, y=10), dir=Direction.NORTH
+    )
+    rov.forward()
+    rov.forward()
+    assert rov.pos == Vector(x=0, y=2)
+
+
+def test_rover_can_go_forward_going_east():
+    rov = Rover(
+        pos=Vector(x=0, y=0), planet_size=Vector(x=10, y=10), dir=Direction.EAST
+    )
+    rov.forward()
+    assert rov.pos == Vector(x=1, y=0)
+
+
+def test_rover_can_go_forward_going_south():
+    rov = Rover(
+        pos=Vector(x=0, y=1), planet_size=Vector(x=10, y=10), dir=Direction.SOUTH
+    )
+    rov.forward()
+    assert rov.pos == Vector(x=0, y=0)
+
+
+def test_rover_can_go_forward_going_west():
+    rov = Rover(
+        pos=Vector(x=1, y=0), planet_size=Vector(x=10, y=10), dir=Direction.WEST
+    )
+    rov.forward()
+    assert rov.pos == Vector(x=0, y=0)