def test_lower_boundary(self):
n = 2
p1 = 0.333 # 33.3%
p2 = 0.334 # 33.4%
self.assertEqual(rank(p1, n), 1)
# can't use assertEqual here b/c floating point numbers
self.assertAlmostEqual(rank(p2, n), p2 * (n + 1))
def test_upper_boundary(self):
n = 4
p1 = 0.80 # 80%
p2 = 0.799 # 79.9%
# should trigger the 3rd case
self.assertEqual(rank(p1, n), n)
# should trigger the second case
self.assertAlmostEqual(rank(p2, n), p2 * (n + 1))
def test_median(self):
for n in range(1, 14):
with self.subTest(size=n):
x = rank(0.5, n)
midpoint = (n + 1) / 2
self.assertEqual(x, midpoint)
def test_excluded_percentile(self):
with self.assertRaises(PercentileBoundsError):
rank(0, 100)
with self.assertRaises(PercentileBoundsError):
rank(1, 100)
def test_one_sample_size(self):
for p in range(1, 100):
with self.subTest(p=p):
x = rank(p / 100, 1)
self.assertEqual(x, 1)
def test_zero_sample_size(self):
for p in range(1, 10):
x = rank(p / 10, 0)
self.assertEqual(x, 1)