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import six |
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from hamcrest.core.base_matcher import BaseMatcher |
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from math import fabs |
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__author__ = "Jon Reid" |
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__copyright__ = "Copyright 2011 hamcrest.org" |
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__license__ = "BSD, see License.txt" |
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def isnumeric(value): |
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"""Confirm that 'value' can be treated numerically; duck-test accordingly |
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""" |
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if isinstance(value, (float, complex) + six.integer_types): |
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return True |
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try: |
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_ = (fabs(value) + 0 - 0) * 1 |
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return True |
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except ArithmeticError: |
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return True |
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except: |
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return False |
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return False |
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class IsCloseTo(BaseMatcher): |
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def __init__(self, value, delta): |
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if not isnumeric(value): |
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raise TypeError('IsCloseTo value must be numeric') |
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if not isnumeric(delta): |
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raise TypeError('IsCloseTo delta must be numeric') |
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self.value = value |
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self.delta = delta |
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def _matches(self, item): |
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if not isnumeric(item): |
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return False |
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return fabs(item - self.value) <= self.delta |
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def describe_mismatch(self, item, mismatch_description): |
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if not isnumeric(item): |
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super(IsCloseTo, self).describe_mismatch(item, mismatch_description) |
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else: |
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actual_delta = fabs(item - self.value) |
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mismatch_description.append_description_of(item) \ |
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.append_text(' differed by ') \ |
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.append_description_of(actual_delta) |
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def describe_to(self, description): |
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description.append_text('a numeric value within ') \ |
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.append_description_of(self.delta) \ |
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.append_text(' of ') \ |
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.append_description_of(self.value) |
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def close_to(value, delta): |
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"""Matches if object is a number close to a given value, within a given |
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delta. |
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:param value: The value to compare against as the expected value. |
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:param delta: The maximum delta between the values for which the numbers |
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are considered close. |
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This matcher compares the evaluated object against ``value`` to see if the |
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difference is within a positive ``delta``. |
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Example:: |
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close_to(3.0, 0.25) |
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""" |
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return IsCloseTo(value, delta) |
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