Method test_sample_with_counts

Lib/test/test_random.py:205–259

(self)

            self.gen.sample(population, k=2)

    def test_sample_with_counts(self):
        sample = self.gen.sample

        # General case
        colors = ['red', 'green', 'blue', 'orange', 'black', 'brown', 'amber']
        counts = [500,      200,     20,       10,       5,       0,       1 ]
        k = 700
        summary = Counter(sample(colors, counts=counts, k=k))
        self.assertEqual(sum(summary.values()), k)
        for color, weight in zip(colors, counts):
            self.assertLessEqual(summary[color], weight)
        self.assertNotIn('brown', summary)

        # Case that exhausts the population
        k = sum(counts)
        summary = Counter(sample(colors, counts=counts, k=k))
        self.assertEqual(sum(summary.values()), k)
        for color, weight in zip(colors, counts):
            self.assertLessEqual(summary[color], weight)
        self.assertNotIn('brown', summary)

        # Case with population size of 1
        summary = Counter(sample(['x'], counts=[10], k=8))
        self.assertEqual(summary, Counter(x=8))

        # Case with all counts equal.
        nc = len(colors)
        summary = Counter(sample(colors, counts=[10]*nc, k=10*nc))
        self.assertEqual(summary, Counter(10*colors))

        # Test error handling
        with self.assertRaises(TypeError):
            sample(['red', 'green', 'blue'], counts=10, k=10)               # counts not iterable
        with self.assertRaises(ValueError):
            sample(['red', 'green', 'blue'], counts=[-3, -7, -8], k=2)      # counts are negative
        with self.assertRaises(ValueError):
            sample(['red', 'green'], counts=[10, 10], k=21)                 # population too small
        with self.assertRaises(ValueError):
            sample(['red', 'green', 'blue'], counts=[1, 2], k=2)            # too few counts
        with self.assertRaises(ValueError):
            sample(['red', 'green', 'blue'], counts=[1, 2, 3, 4], k=2)      # too many counts

        # Cases with zero counts match equivalents without counts (see gh-130285)
        self.assertEqual(
            sample('abc', k=0, counts=[0, 0, 0]),
            sample([], k=0),
        )
        self.assertEqual(
            sample([], 0, counts=[]),
            sample([], 0),
        )
        with self.assertRaises(ValueError):
            sample([], 1, counts=[])
        with self.assertRaises(ValueError):
            sample('x', 1, counts=[0])

    def test_choices(self):
        choices = self.gen.choices