Test failure in test_frac.py for function float_to_twelths_frac #14
Description
With Python 3.10.0 and 3.12.5 on macOS 14.7, running pytest produces a failure in test_frac.py:
def test_float_to_twelths_frac() -> None:
with pytest.raises(ValueError):
u.float_to_twelths_frac(1.0 / 24)
with pytest.raises(ValueError):
u.float_to_twelths_frac(1.0 / 7)
with pytest.raises(ValueError):
u.float_to_twelths_frac(1.0 / 5)
with pytest.raises(ValueError):
u.float_to_twelths_frac(1.0 / 11)
with pytest.raises(ValueError):
u.float_to_twelths_frac(1.0 / 13)
assert u.float_to_twelths_frac(0) == frac(0)
assert u.float_to_twelths_frac(502) == frac(502)
assert u.float_to_twelths_frac(1.0 / 12) == frac(denom=12)
assert u.float_to_twelths_frac(-1.0 / 12) == frac(-1, 12)
assert u.float_to_twelths_frac(501.0 / 3) == frac(167)
assert u.float_to_twelths_frac(502.0 / 3) == frac(502, 3)
# Precision.
assert u.float_to_twelths_frac((1 << 55) + 1) == frac((1 << 55) + 1)
> assert u.float_to_twelths_frac(float(1 << 55) / 3.0) == frac(1 << 55, 3)
test/cython/test_frac.py:128:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
tunits/core/cython/frac.pyx:83: in tunits_core.float_to_twelths_frac
cpdef frac float_to_twelths_frac(a) except *:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
> raise ValueError("Not a twelfth.")
E ValueError: Not a twelfth.
tunits/core/cython/frac.pyx:91: ValueError
This is using a fresh pyenv virtual environment, then installing dependencies using
pip install -r dev_tools/dev.env.txtfollowed by running pytest. Stopping in the test function and inspecting the values, it appears that the difference between values for the case involving float(1 << 55 / 3.0) is indeed greater than the absolute tolerance specified.
I don't experience this on Linux.