def setUp(self):
# Generate random results, calculate intermediate values for those
# results.
self.random_results = [random.choice(THINGS) for _ in range(50)]
self.past_counts = oracle.count_past_events(
self.random_results, LARGE_WINDOW)
self.weights = oracle.calculate_weights(
THINGS, self.past_counts, LARGE_WINDOW)
self.cdf = oracle.calculate_cdf(self.weights)
self.random_thing = oracle.sample_cdf(self.cdf)
def test_calculate_weights(self):
# No existing results, all weights should be equal to base chance.
zero_counts = collections.defaultdict(int)
self.assertEqual({
'a': BASE_CHANCE,
'b': BASE_CHANCE,
'c': BASE_CHANCE,
'd': BASE_CHANCE,
}, oracle.calculate_weights(THINGS, zero_counts, LARGE_WINDOW))
# Window full of single result, weights should be split between all
# other choices.
results = ('c', 'c', 'c', 'c')
past_counts = oracle.count_past_events(results, SMALL_WINDOW)
one_third = 1 / float(3)
self.assertEqual({'a': one_third, 'b': one_third, 'd': one_third},
oracle.calculate_weights(THINGS, past_counts, SMALL_WINDOW))
# Weights should be normalized to (0, 1] range.
self.assertNotIn(False, [1 >= w >= 0 for w in self.weights.values()])
# All keys of weights should be THINGS.
self.assertNotIn(False, [thing in THINGS for thing in self.weights])
