Problem with BOOST_CHECK_CLOSE_FRACTION

boost, boost-test, c++

Solution

After some testing, it turns out that the documentation for BOOST_CHECK_CLOSE_FRACTION is incorrect. The tolerance should be specified as a fraction of the expected value.

So, TFAE:

BOOST_CHECK(abs(x - y) < (min(x, y) * 0.1));
BOOST_CHECK_CLOSE(x, y, 10);
BOOST_CHECK_CLOSE_FRACTION(x, y, 0.1);

Problem

I'm using the Boost::Test library, and I am trying to check if an actual percent value is close to the expected value: ``` BOOST_CHECK_CLOSE_FRACTION( items[i].ExpectedPercent, items[i].ActualCount / totalCount, 0.05); ``` For some reason this check fails even when the values are close enough: ``` difference between items[i].ExpectedPercent{0.40000000000000002} and items[i].ActualCount / totalReturned{0.42999999999999999} exceeds 0.050000000000000003 ``` Is this a problem with Boost or a problem with how I am using Boost?

Original source