atbash, robot simulator, sum of multiples exercises

python/robot-simulator/.exercism/metadata.json

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+{"track":"python","exercise":"robot-simulator","id":"257266d04daa4093a7d60012d0c003ef","url":"https://exercism.io/my/solutions/257266d04daa4093a7d60012d0c003ef","handle":"Xevion","is_requester":true,"auto_approve":false}

python/robot-simulator/README.md

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+# Robot Simulator
+
+Write a robot simulator.
+
+A robot factory's test facility needs a program to verify robot movements.
+
+The robots have three possible movements:
+
+- turn right
+- turn left
+- advance
+
+Robots are placed on a hypothetical infinite grid, facing a particular
+direction (north, east, south, or west) at a set of {x,y} coordinates,
+e.g., {3,8}, with coordinates increasing to the north and east.
+
+The robot then receives a number of instructions, at which point the
+testing facility verifies the robot's new position, and in which
+direction it is pointing.
+
+- The letter-string "RAALAL" means:
+  - Turn right
+  - Advance twice
+  - Turn left
+  - Advance once
+  - Turn left yet again
+- Say a robot starts at {7, 3} facing north. Then running this stream
+  of instructions should leave it at {9, 4} facing west.
+
+## Exception messages
+
+Sometimes it is necessary to raise an exception. When you do this, you should include a meaningful error message to
+indicate what the source of the error is. This makes your code more readable and helps significantly with debugging. Not
+every exercise will require you to raise an exception, but for those that do, the tests will only pass if you include
+a message.
+
+To raise a message with an exception, just write it as an argument to the exception type. For example, instead of
+`raise Exception`, you should write:
+
+```python
+raise Exception("Meaningful message indicating the source of the error")
+```
+
+## Running the tests
+
+To run the tests, run the appropriate command below ([why they are different](https://github.com/pytest-dev/pytest/issues/1629#issue-161422224)):
+
+- Python 2.7: `py.test robot_simulator_test.py`
+- Python 3.4+: `pytest robot_simulator_test.py`
+
+Alternatively, you can tell Python to run the pytest module (allowing the same command to be used regardless of Python version):
+`python -m pytest robot_simulator_test.py`
+
+### Common `pytest` options
+
+- `-v` : enable verbose output
+- `-x` : stop running tests on first failure
+- `--ff` : run failures from previous test before running other test cases
+
+For other options, see `python -m pytest -h`
+
+## Submitting Exercises
+
+Note that, when trying to submit an exercise, make sure the solution is in the `$EXERCISM_WORKSPACE/python/robot-simulator` directory.
+
+You can find your Exercism workspace by running `exercism debug` and looking for the line that starts with `Workspace`.
+
+For more detailed information about running tests, code style and linting,
+please see [Running the Tests](http://exercism.io/tracks/python/tests).
+
+## Source
+
+Inspired by an interview question at a famous company.
+
+## Submitting Incomplete Solutions
+
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.

python/robot-simulator/robot_simulator.py

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+import re
+
+# Globals for the bearings
+# Change the values as you see fit
+EAST = (1, 0)
+NORTH = (0, 1)
+WEST = (-1, 0)
+SOUTH = (0, -1)
+BEARINGS = [NORTH, EAST, SOUTH, WEST]
+BEARINGSF = ['North', 'East', 'South', 'West']
+
+class Robot(object):
+    def __init__(self, bearing=NORTH, x=0, y=0):
+        self.x, self.y, self.bearing = x, y, bearing
+        self.turn_left, self.turn_right = lambda : self.turn(), lambda : self.turn(isright=True)    
+    @property
+    def coordinates(self):
+        return (self.x, self.y)
+
+    def simulate(self, commands):
+        [self.turn(True, n=len(c)) if c[0] == 'R' else self.turn(n=len(c)) if c[0] == 'L' else self.advance(n=len(c)) if c[0] == 'A' else None for c in map(lambda item : item[0], re.finditer(r'(\w)\1*', commands))]
+    
+    def advance(self, n=1):
+        self.x, self.y = self.x + (self.bearing[0] * n), self.y + (self.bearing[1] * n)
+
+    def turn(self, isright=False, n=1):
+        for _ in range(n):
+            index = (BEARINGS.index(self.bearing) + (1 if isright else -1))
+            self.bearing = BEARINGS[0 if index == 4 else index]
+
+    def __repr__(self):
+        return f'<Robot ({self.x}, {self.y})/{BEARINGSF[BEARINGS.index(self.bearing)]}>'

python/robot-simulator/robot_simulator_test.py

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+import unittest
+
+from robot_simulator import Robot, NORTH, EAST, SOUTH, WEST
+
+
+# Tests adapted from `problem-specifications//canonical-data.json` @ v3.2.0
+
+class RobotSimulatorTest(unittest.TestCase):
+
+    def test_create_robot_at_origin_facing_north(self):
+        robot = Robot(NORTH, 0, 0)
+        self.assertEqual(robot.coordinates, (0, 0))
+        self.assertEqual(robot.bearing, NORTH)
+
+    def test_create_robot_at_negative_position_facing_south(self):
+        robot = Robot(SOUTH, -1, -1)
+        self.assertEqual(robot.coordinates, (-1, -1))
+        self.assertEqual(robot.bearing, SOUTH)
+
+    def test_rotating_clockwise(self):
+        dirA = [NORTH, EAST, SOUTH, WEST]
+        dirB = [EAST, SOUTH, WEST, NORTH]
+        for x in range(len(dirA)):
+            robot = Robot(dirA[x], 0, 0)
+            robot.turn_right()
+            self.assertEqual(robot.bearing, dirB[x])
+
+    def test_rotating_clockwise_by_simulate_R(self):
+        A = [NORTH, EAST, SOUTH, WEST]
+        B = [EAST, SOUTH, WEST, NORTH]
+        for x in range(len(A)):
+            robot = Robot(A[x], 0, 0)
+            robot.simulate("R")
+            self.assertEqual(robot.bearing, B[x])
+
+    def test_rotating_counter_clockwise(self):
+        dirA = [NORTH, EAST, SOUTH, WEST]
+        dirB = [WEST, NORTH, EAST, SOUTH]
+        for x in range(len(dirA)):
+            robot = Robot(dirA[x], 0, 0)
+            robot.turn_left()
+            self.assertEqual(robot.bearing, dirB[x])
+
+    def test_rotating_counter_clockwise_by_simulate_L(self):
+        A = [NORTH, WEST, SOUTH, EAST]
+        B = [WEST, SOUTH, EAST, NORTH]
+        for x in range(len(A)):
+            robot = Robot(A[x], 0, 0)
+            robot.simulate("L")
+            self.assertEqual(robot.bearing, B[x])
+
+    def test_moving_forward_one_facing_north_increments_Y(self):
+        robot = Robot(NORTH, 0, 0)
+        robot.advance()
+        self.assertEqual(robot.coordinates, (0, 1))
+        self.assertEqual(robot.bearing, NORTH)
+
+    def test_moving_forward_one_facing_south_decrements_Y(self):
+        robot = Robot(SOUTH, 0, 0)
+        robot.advance()
+        self.assertEqual(robot.coordinates, (0, -1))
+        self.assertEqual(robot.bearing, SOUTH)
+
+    def test_moving_forward_one_facing_east_increments_X(self):
+        robot = Robot(EAST, 0, 0)
+        robot.advance()
+        self.assertEqual(robot.coordinates, (1, 0))
+        self.assertEqual(robot.bearing, EAST)
+
+    def test_moving_forward_one_facing_west_decrements_X(self):
+        robot = Robot(WEST, 0, 0)
+        robot.advance()
+        self.assertEqual(robot.coordinates, (-1, 0))
+        self.assertEqual(robot.bearing, WEST)
+
+    def test_series_of_instructions_moving_east_and_north_from_README(self):
+        robot = Robot(NORTH, 7, 3)
+        robot.simulate("RAALAL")
+        self.assertEqual(robot.coordinates, (9, 4))
+        self.assertEqual(robot.bearing, WEST)
+
+    def test_series_of_instructions_moving_west_and_north(self):
+        robot = Robot(NORTH, 0, 0)
+        robot.simulate("LAAARALA")
+        self.assertEqual(robot.coordinates, (-4, 1))
+        self.assertEqual(robot.bearing, WEST)
+
+    def test_series_of_instructions_moving_west_and_south(self):
+        robot = Robot(EAST, 2, -7)
+        robot.simulate("RRAAAAALA")
+        self.assertEqual(robot.coordinates, (-3, -8))
+        self.assertEqual(robot.bearing, SOUTH)
+
+    def test_series_of_instructions_moving_east_and_north(self):
+        robot = Robot(SOUTH, 8, 4)
+        robot.simulate("LAAARRRALLLL")
+        self.assertEqual(robot.coordinates, (11, 5))
+        self.assertEqual(robot.bearing, NORTH)
+
+
+if __name__ == '__main__':
+    unittest.main()