test_turn_picker.py

#!/usr/bin/env python
from unittest import TestCase, main

from turn_picker import score


class TurnPickerTest(TestCase):

    def test_score_low_vs_high_attendance(self):
        self.assertGreater(score(2, 10, 0), score(50, 200, 12))
        self.assertLess(score(3, 15, 0), score(50, 200, 12))

    def test_score_ab_two_events(self):
        # A has watched B's movie
        # B should watch A's movie
        self.assertTrue(score(1, 2, 0) < score(1, 2, 1))

    def test_around_zero(self):
        self.assertGreater(score(1, 2, 0), 0)
        self.assertEqual(score(2, 4, 0), 0)
        self.assertLess(score(3, 6, 0), 0)

    def test_score_ab_lots_of_events(self):
        # A has watched B's movie
        # B has gone to many movie nights, A has only gone to 1
        # B should watch A's movie on the third time
        self.assertGreater(score(1, 2, 0), score(40, 80, 19))
        self.assertEqual(score(2, 4, 0), score(40, 80, 19))

    def test_average_attendance_difference(self):
        self.assertLess(score(3, 15, 1), score(3, 115, 1))

    def test_large_numbers(self):
        # Many vs. Few events attended
        self.assertLess(score(100, 400, 24), score(10000, 40000, 2500))
        self.assertGreater(score(100, 400, 25), score(10000, 40000, 2499))
        self.assertEqual(score(100, 400, 24), score(10000, 40000, 2499))

        # Low vs. High attendance
        self.assertLess(score(100, 400, 25), score(100, 1000, 10))
        self.assertGreater(score(100, 400, 25), score(100, 1000, 9))
        self.assertLess(score(100, 400, 24), score(100, 1000, 10))
        self.assertEqual(score(100, 400, 24), score(100, 1000, 9))

if __name__ == "__main__":
    main()

turn_picker.py

from __future__ import division
from math import log


def score(events_attended, people_attended, times_picked):
    average_attendance = people_attended / events_attended
    exp_score = average_attendance * (times_picked + 1) / events_attended
    return log(exp_score, average_attendance) * people_attended