Current File : //usr/lib/python3/dist-packages/hamcrest/library/number/iscloseto.py
from decimal import Decimal
from math import fabs
from typing import Any, Union, overload
from hamcrest.core.base_matcher import BaseMatcher
from hamcrest.core.description import Description
from hamcrest.core.matcher import Matcher
__author__ = "Jon Reid"
__copyright__ = "Copyright 2011 hamcrest.org"
__license__ = "BSD, see License.txt"
Number = Union[float, Decimal] # Argh, https://github.com/python/mypy/issues/3186
def isnumeric(value: Any) -> bool:
"""Confirm that 'value' can be treated numerically; duck-test accordingly
"""
if isinstance(value, (float, complex, int)):
return True
try:
_ = (fabs(value) + 0 - 0) * 1
return True
except ArithmeticError:
return True
except:
return False
class IsCloseTo(BaseMatcher[Number]):
def __init__(self, value: Number, delta: Number) -> None:
if not isnumeric(value):
raise TypeError("IsCloseTo value must be numeric")
if not isnumeric(delta):
raise TypeError("IsCloseTo delta must be numeric")
self.value = value
self.delta = delta
def _matches(self, item: Number) -> bool:
if not isnumeric(item):
return False
return self._diff(item) <= self.delta
def _diff(self, item: Number) -> float:
# TODO - Fails for mixed floats & Decimals
return fabs(item - self.value) # type: ignore
def describe_mismatch(self, item: Number, mismatch_description: Description) -> None:
if not isnumeric(item):
super(IsCloseTo, self).describe_mismatch(item, mismatch_description)
else:
actual_delta = self._diff(item)
mismatch_description.append_description_of(item).append_text(
" differed by "
).append_description_of(actual_delta)
def describe_to(self, description: Description) -> None:
description.append_text("a numeric value within ").append_description_of(
self.delta
).append_text(" of ").append_description_of(self.value)
@overload
def close_to(value: float, delta: float) -> Matcher[float]:
...
@overload
def close_to(value: Decimal, delta: Decimal) -> Matcher[Decimal]:
...
def close_to(value, delta):
"""Matches if object is a number close to a given value, within a given
delta.
:param value: The value to compare against as the expected value.
:param delta: The maximum delta between the values for which the numbers
are considered close.
This matcher compares the evaluated object against ``value`` to see if the
difference is within a positive ``delta``.
Example::
close_to(3.0, 0.25)
"""
return IsCloseTo(value, delta)
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