def test_precision_at_k_extrapolate():
y_true = np.array([True, False, np.nan])
y_score = np.array([1, 0, .5])
p,s = precision_at_k(y_true, y_score,3, extrapolate=True)
assert p == .5
assert_almost_equal(s, 1/np.sqrt(8))
def test_precision_at_k():
y_true = np.array([True, True, False])
y_score = np.array([1, 0, .5])
assert precision_at_k(y_true, y_score,2) == .5
