287 lines
9.6 KiB
Python
287 lines
9.6 KiB
Python
# encoding: utf-8
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import pytest
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import doctest
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from pytest import approx
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from operator import eq, ne
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from decimal import Decimal
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from fractions import Fraction
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inf, nan = float('inf'), float('nan')
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class MyDocTestRunner(doctest.DocTestRunner):
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def __init__(self):
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doctest.DocTestRunner.__init__(self)
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def report_failure(self, out, test, example, got):
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raise AssertionError("'{}' evaluates to '{}', not '{}'".format(
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example.source.strip(), got.strip(), example.want.strip()))
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class TestApprox:
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def test_repr_string(self):
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# Just make sure the Unicode handling doesn't raise any exceptions.
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print(approx(1.0))
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print(approx([1.0, 2.0, 3.0]))
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print(approx(inf))
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print(approx(1.0, rel=nan))
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print(approx(1.0, rel=inf))
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def test_operator_overloading(self):
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assert 1 == approx(1, rel=1e-6, abs=1e-12)
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assert not (1 != approx(1, rel=1e-6, abs=1e-12))
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assert 10 != approx(1, rel=1e-6, abs=1e-12)
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assert not (10 == approx(1, rel=1e-6, abs=1e-12))
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def test_exactly_equal(self):
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examples = [
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(2.0, 2.0),
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(0.1e200, 0.1e200),
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(1.123e-300, 1.123e-300),
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(12345, 12345.0),
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(0.0, -0.0),
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(345678, 345678),
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(Decimal('1.0001'), Decimal('1.0001')),
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(Fraction(1, 3), Fraction(-1, -3)),
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]
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for a, x in examples:
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assert a == approx(x)
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def test_opposite_sign(self):
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examples = [
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(eq, 1e-100, -1e-100),
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(ne, 1e100, -1e100),
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]
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for op, a, x in examples:
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assert op(a, approx(x))
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def test_zero_tolerance(self):
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within_1e10 = [
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(1.1e-100, 1e-100),
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(-1.1e-100, -1e-100),
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]
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for a, x in within_1e10:
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assert x == approx(x, rel=0.0, abs=0.0)
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assert a != approx(x, rel=0.0, abs=0.0)
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assert a == approx(x, rel=0.0, abs=5e-101)
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assert a != approx(x, rel=0.0, abs=5e-102)
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assert a == approx(x, rel=5e-1, abs=0.0)
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assert a != approx(x, rel=5e-2, abs=0.0)
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def test_negative_tolerance(self):
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# Negative tolerances are not allowed.
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illegal_kwargs = [
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dict(rel=-1e100),
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dict(abs=-1e100),
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dict(rel=1e100, abs=-1e100),
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dict(rel=-1e100, abs=1e100),
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dict(rel=-1e100, abs=-1e100),
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]
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for kwargs in illegal_kwargs:
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with pytest.raises(ValueError):
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1.1 == approx(1, **kwargs)
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def test_inf_tolerance(self):
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# Everything should be equal if the tolerance is infinite.
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large_diffs = [
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(1, 1000),
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(1e-50, 1e50),
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(-1.0, -1e300),
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(0.0, 10),
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]
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for a, x in large_diffs:
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assert a != approx(x, rel=0.0, abs=0.0)
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assert a == approx(x, rel=inf, abs=0.0)
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assert a == approx(x, rel=0.0, abs=inf)
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assert a == approx(x, rel=inf, abs=inf)
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def test_inf_tolerance_expecting_zero(self):
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# If the relative tolerance is zero but the expected value is infinite,
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# the actual tolerance is a NaN, which should be an error.
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illegal_kwargs = [
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dict(rel=inf, abs=0.0),
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dict(rel=inf, abs=inf),
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]
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for kwargs in illegal_kwargs:
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with pytest.raises(ValueError):
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1 == approx(0, **kwargs)
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def test_nan_tolerance(self):
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illegal_kwargs = [
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dict(rel=nan),
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dict(abs=nan),
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dict(rel=nan, abs=nan),
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]
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for kwargs in illegal_kwargs:
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with pytest.raises(ValueError):
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1.1 == approx(1, **kwargs)
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def test_reasonable_defaults(self):
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# Whatever the defaults are, they should work for numbers close to 1
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# than have a small amount of floating-point error.
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assert 0.1 + 0.2 == approx(0.3)
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def test_default_tolerances(self):
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# This tests the defaults as they are currently set. If you change the
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# defaults, this test will fail but you should feel free to change it.
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# None of the other tests (except the doctests) should be affected by
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# the choice of defaults.
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examples = [
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# Relative tolerance used.
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(eq, 1e100 + 1e94, 1e100),
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(ne, 1e100 + 2e94, 1e100),
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(eq, 1e0 + 1e-6, 1e0),
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(ne, 1e0 + 2e-6, 1e0),
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# Absolute tolerance used.
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(eq, 1e-100, + 1e-106),
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(eq, 1e-100, + 2e-106),
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(eq, 1e-100, 0),
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]
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for op, a, x in examples:
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assert op(a, approx(x))
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def test_custom_tolerances(self):
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assert 1e8 + 1e0 == approx(1e8, rel=5e-8, abs=5e0)
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assert 1e8 + 1e0 == approx(1e8, rel=5e-9, abs=5e0)
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assert 1e8 + 1e0 == approx(1e8, rel=5e-8, abs=5e-1)
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assert 1e8 + 1e0 != approx(1e8, rel=5e-9, abs=5e-1)
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assert 1e0 + 1e-8 == approx(1e0, rel=5e-8, abs=5e-8)
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assert 1e0 + 1e-8 == approx(1e0, rel=5e-9, abs=5e-8)
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assert 1e0 + 1e-8 == approx(1e0, rel=5e-8, abs=5e-9)
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assert 1e0 + 1e-8 != approx(1e0, rel=5e-9, abs=5e-9)
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assert 1e-8 + 1e-16 == approx(1e-8, rel=5e-8, abs=5e-16)
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assert 1e-8 + 1e-16 == approx(1e-8, rel=5e-9, abs=5e-16)
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assert 1e-8 + 1e-16 == approx(1e-8, rel=5e-8, abs=5e-17)
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assert 1e-8 + 1e-16 != approx(1e-8, rel=5e-9, abs=5e-17)
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def test_relative_tolerance(self):
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within_1e8_rel = [
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(1e8 + 1e0, 1e8),
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(1e0 + 1e-8, 1e0),
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(1e-8 + 1e-16, 1e-8),
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]
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for a, x in within_1e8_rel:
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assert a == approx(x, rel=5e-8, abs=0.0)
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assert a != approx(x, rel=5e-9, abs=0.0)
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def test_absolute_tolerance(self):
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within_1e8_abs = [
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(1e8 + 9e-9, 1e8),
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(1e0 + 9e-9, 1e0),
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(1e-8 + 9e-9, 1e-8),
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]
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for a, x in within_1e8_abs:
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assert a == approx(x, rel=0, abs=5e-8)
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assert a != approx(x, rel=0, abs=5e-9)
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def test_expecting_zero(self):
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examples = [
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(ne, 1e-6, 0.0),
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(ne, -1e-6, 0.0),
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(eq, 1e-12, 0.0),
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(eq, -1e-12, 0.0),
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(ne, 2e-12, 0.0),
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(ne, -2e-12, 0.0),
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(ne, inf, 0.0),
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(ne, nan, 0.0),
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]
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for op, a, x in examples:
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assert op(a, approx(x, rel=0.0, abs=1e-12))
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assert op(a, approx(x, rel=1e-6, abs=1e-12))
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def test_expecting_inf(self):
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examples = [
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(eq, inf, inf),
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(eq, -inf, -inf),
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(ne, inf, -inf),
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(ne, 0.0, inf),
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(ne, nan, inf),
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]
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for op, a, x in examples:
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assert op(a, approx(x))
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def test_expecting_nan(self):
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examples = [
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(nan, nan),
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(-nan, -nan),
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(nan, -nan),
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(0.0, nan),
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(inf, nan),
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]
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for a, x in examples:
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# If there is a relative tolerance and the expected value is NaN,
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# the actual tolerance is a NaN, which should be an error.
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with pytest.raises(ValueError):
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a != approx(x, rel=inf)
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# You can make comparisons against NaN by not specifying a relative
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# tolerance, so only an absolute tolerance is calculated.
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assert a != approx(x, abs=inf)
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def test_expecting_sequence(self):
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within_1e8 = [
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(1e8 + 1e0, 1e8),
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(1e0 + 1e-8, 1e0),
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(1e-8 + 1e-16, 1e-8),
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]
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actual, expected = zip(*within_1e8)
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assert actual == approx(expected, rel=5e-8, abs=0.0)
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def test_expecting_sequence_wrong_len(self):
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assert [1, 2] != approx([1])
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assert [1, 2] != approx([1,2,3])
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def test_complex(self):
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within_1e6 = [
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( 1.000001 + 1.0j, 1.0 + 1.0j),
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(1.0 + 1.000001j, 1.0 + 1.0j),
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(-1.000001 + 1.0j, -1.0 + 1.0j),
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(1.0 - 1.000001j, 1.0 - 1.0j),
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]
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for a, x in within_1e6:
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assert a == approx(x, rel=5e-6, abs=0)
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assert a != approx(x, rel=5e-7, abs=0)
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def test_int(self):
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within_1e6 = [
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(1000001, 1000000),
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(-1000001, -1000000),
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]
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for a, x in within_1e6:
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assert a == approx(x, rel=5e-6, abs=0)
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assert a != approx(x, rel=5e-7, abs=0)
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def test_decimal(self):
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within_1e6 = [
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(Decimal('1.000001'), Decimal('1.0')),
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(Decimal('-1.000001'), Decimal('-1.0')),
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]
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for a, x in within_1e6:
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assert a == approx(x, rel=Decimal('5e-6'), abs=0)
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assert a != approx(x, rel=Decimal('5e-7'), abs=0)
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def test_fraction(self):
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within_1e6 = [
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(1 + Fraction(1, 1000000), Fraction(1)),
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(-1 - Fraction(-1, 1000000), Fraction(-1)),
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]
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for a, x in within_1e6:
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assert a == approx(x, rel=5e-6, abs=0)
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assert a != approx(x, rel=5e-7, abs=0)
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def test_doctests(self):
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parser = doctest.DocTestParser()
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test = parser.get_doctest(
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approx.__doc__,
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{'approx': approx},
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approx.__name__,
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None, None,
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)
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runner = MyDocTestRunner()
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runner.run(test)
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