https://github.com/guardian/pairing-tests/tree/master/warehouse-robot

robot.py

from enum import Enum, unique


@unique
class Direction(Enum):
    north, east, south, west = range(1, 5)

    def offset(self):
        if self is Direction.north:
            return [0, -1]
        elif self is Direction.east:
            return [1, 0]
        elif self is Direction.south:
            return [0, 1]
        elif self is Direction.west:
            return [-1, 0]
        else:
            raise ValueError("Unhandled direction.")


class Robot:
    def __init__(self):
        self.position = [0, 0]

    def move(self, direction):
        if direction not in Direction:
            raise ValueError("Invalid direction '%s'." % direction)
        direction_offset = direction.offset()
        self.position[0] += direction_offset[0]
        self.position[1] += direction_offset[1]

robot_test.py

import os
import unittest
from robot import Robot, Direction


class DirectionTestCase(unittest.TestCase):
    def test_offsets(self):
        self.assertEqual(Direction.north.offset(), [0, -1])
        self.assertEqual(Direction.east.offset(), [1, 0])
        self.assertEqual(Direction.south.offset(), [0, 1])
        self.assertEqual(Direction.west.offset(), [-1, 0])


class RobotTestCase(unittest.TestCase):
    def test_start_position(self):
        self.assertEqual(self.robot.position, [0, 0])

    def test_move_basic(self):
        for direction in Direction.__members__.values():
            self.robot = Robot()
            self.robot.move(direction)
            self.assertEqual(self.robot.position, direction.offset())

    def test_move_invalid(self):
        with self.assertRaises(ValueError):
            self.robot.move("abc")

    def setUp(self):
        self.robot = Robot()

    def tearDown(self):
        pass


if __name__ == '__main__':
    unittest.main()