boltons/tests/test_mathutils.py

from pytest import raises
from boltons.mathutils import clamp, ceil, floor, Bits
import math

INF, NAN = float('inf'), float('nan')

OPTIONS = [1618, 1378, 166, 1521, 2347, 2016, 879, 2123,
           269.3, 1230, 66, 425.2, 250, 2399, 2314, 439,
           247, 208, 379, 1861]
OPTIONS_SORTED = sorted(OPTIONS)
OUT_OF_RANGE_LOWER = 60
OUT_OF_RANGE_UPPER = 2500
VALID_LOWER = 247
VALID_UPPER = 2314
VALID_BETWEEN = 248.5

def test_clamp_examples():
    """some examples for clamp()"""
    assert 0 == clamp(0, 0, 1) == clamp(-1, 0, 1)
    assert 0 == clamp(-1, lower=0)
    assert 1 == clamp(1, 0, 1) == clamp(5, 0, 1)
    assert 1 == clamp(5, upper=1)
    assert 0.5 == clamp(7, upper=0.5)
    assert 1 == clamp(7.7, upper=1)

def test_clamp_transparent():
    """clamp(x) should equal x because both limits are omitted"""
    assert clamp(0) == 0
    assert clamp(1) == 1
    assert clamp(10**100) == 10**100
    assert clamp(INF) == INF
    assert clamp(-INF) == -INF
    assert math.isnan(clamp(NAN))


def test_ceil_basic():
    assert ceil(VALID_LOWER, OPTIONS) == VALID_LOWER
    assert ceil(VALID_UPPER, OPTIONS) == VALID_UPPER
    assert ceil(VALID_BETWEEN, OPTIONS) == 250


def test_ceil_sorted():
    assert ceil(VALID_LOWER, OPTIONS) == ceil(VALID_LOWER, OPTIONS_SORTED)
    assert ceil(VALID_UPPER, OPTIONS) == ceil(VALID_UPPER, OPTIONS_SORTED)
    assert ceil(VALID_BETWEEN, OPTIONS) == ceil(VALID_BETWEEN, OPTIONS_SORTED)


def test_ceil_oor_lower():
    assert min(OPTIONS) == ceil(OUT_OF_RANGE_LOWER, OPTIONS)


def test_ceil_oor_upper():
    with raises(ValueError):
        ceil(OUT_OF_RANGE_UPPER, OPTIONS)


def test_floor_basic():
    assert floor(VALID_LOWER, OPTIONS) == VALID_LOWER
    assert floor(VALID_UPPER, OPTIONS) == VALID_UPPER
    assert floor(VALID_LOWER, OPTIONS) == 247


def test_floor_sorted():
    assert floor(VALID_LOWER, OPTIONS) == floor(VALID_LOWER, OPTIONS_SORTED)
    assert floor(VALID_UPPER, OPTIONS) == floor(VALID_UPPER, OPTIONS_SORTED)
    assert floor(VALID_BETWEEN, OPTIONS) == floor(VALID_BETWEEN, OPTIONS_SORTED)


def test_floor_oor_upper():
    assert max(OPTIONS) == floor(OUT_OF_RANGE_UPPER, OPTIONS)


def test_floor_oor_lower():
    with raises(ValueError):
        floor(OUT_OF_RANGE_LOWER, OPTIONS)


def test_bits():
    def chk(a, b):
        assert a == b, a
    chk(Bits('10')[:1], Bits('1'))
    chk(Bits('10')[1:], Bits('0'))
    chk(Bits('10')[0], True)
    chk(Bits('10')[1], False)
    chk(Bits('0000100')[4], True)
    chk(Bits('10').as_list(), [True, False])
    chk(Bits('10').as_int(), 2)
    chk(Bits('10').as_bin(), '10')
    chk(Bits('1111').as_hex(), '0F')
    chk(Bits('10'), Bits([True, False]))
    chk(Bits('10'), Bits(2))
    chk(Bits('01') | Bits('10'), Bits('11'))
    chk(Bits('01') & Bits('10'), Bits('00'))
    chk(Bits('11') >> 1, Bits('1'))
    chk(Bits('1') << 1, Bits('10'))
    assert Bits('0') != Bits('00')
    # test roundtrip as_/from_hex
    chk(Bits.from_hex(Bits('10101010').as_hex()),
        Bits('10101010'))
    # test roundtrip as_/from_bytes
    chk(
        Bits.from_bytes(Bits('10101010').as_bytes()),
        Bits('10101010'))
    # pile of roundtripping
    chk(Bits.from_int(
            Bits.from_bin(
                Bits.from_list(
                    Bits('101').as_list()
                ).as_bin()
            ).as_int()
        ),
        Bits('101'))