From 24b3f63d3c80da224df8e1e637b8b3d36aa9c593 Mon Sep 17 00:00:00 2001
From: Bruno BELANYI <bruno@belanyi.fr>
Date: Fri, 15 Nov 2019 21:12:51 +0100
Subject: [PATCH] rover: wrap when going negative

---
 rover/rover.py      |  5 +++++
 rover/test_rover.py | 16 ++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/rover/rover.py b/rover/rover.py
index 2190364..6fc531b 100644
--- a/rover/rover.py
+++ b/rover/rover.py
@@ -29,3 +29,8 @@ class Rover(BaseModel):
             self.pos.x += 1
         elif self.dir == Direction.WEST:
             self.pos.x -= 1
+
+        if self.pos.x < 0:
+            self.pos.x += self.planet_size.x
+        if self.pos.y < 0:
+            self.pos.y += self.planet_size.y
diff --git a/rover/test_rover.py b/rover/test_rover.py
index f5a00ca..8c6e0a1 100644
--- a/rover/test_rover.py
+++ b/rover/test_rover.py
@@ -60,3 +60,19 @@ def test_rover_can_go_forward_going_west():
     )
     rov.forward()
     assert rov.pos == Vector(x=0, y=0)
+
+
+def test_rover_can_wrap_under_north_south():
+    rov = Rover(
+        pos=Vector(x=0, y=0), planet_size=Vector(x=10, y=10), dir=Direction.SOUTH
+    )
+    rov.forward()
+    assert rov.pos == Vector(x=0, y=9)
+
+
+def test_rover_can_wrap_under_east_west():
+    rov = Rover(
+        pos=Vector(x=0, y=0), planet_size=Vector(x=10, y=10), dir=Direction.WEST
+    )
+    rov.forward()
+    assert rov.pos == Vector(x=9, y=0)