[DOC]: Explain the choice of absolute/relative tolerance for check_less_precise in assert_almost_equal

[rs2]

The docstring in

pandas/pandas/util/testing.py

Lines 226 to 229 in 9e982e1

	check_less_precise : bool or int, default False
	Specify comparison precision. Only used when check_exact is False.
	5 digits (False) or 3 digits (True) after decimal points are compared.
	If int, then specify the digits to compare

does not specify how the number of decimal digits is going to be used, yet

pandas/pandas/_libs/testing.pyx

Lines 203 to 210 in 9e982e1

	if abs(fa) < 1e-5:
	if not decimal_almost_equal(fa, fb, decimal):
	assert False, ('(very low values) expected %.5f but '
	'got %.5f, with decimal %d' % (fb, fa, decimal))
	else:
	if not decimal_almost_equal(1, fb / fa, decimal):
	assert False, ('expected %.5f but got %.5f, '
	'with decimal %d' % (fb, fa, decimal))

switches between absolute and relative tolerance depending on the (hardcoded) magnitude on the number.

[gfyoung]

@rs2 : Nice catch! Would you like to submit a patch for the docs?

[gfyoung]

Marking for 0.23.2, as this is a relatively trivial thing that we should be able to get in (I can bring this to the finish line if others are unable to do so).

[jorisvandenbossche]

@gfyoung removed the milestone. You are of course welcome to do a PR, but I want to keep the milestone focused on the ones that are important for 0.23.2