As per angularsen/UnitsNet#328 (comment)

Having a set of tests to validate that the correct abbreviation notations and symbols are used would be helpful, as we have seen from before that discrepancies tend to creep in over time.

See #328 for the (currently work in progress) guideline, go through the comments and identify what tests to write for the guid

Provide nice Unicode symbols for fractional exponents wherever possible.

using namespace units;
using namespace units::si::literals;

std::cout << sqrt(1m) << "\n";

It came up in #41 that it would be nice to have functions like abs(), sqrt(), etc. implemented on $System<f64, U> (and friends) directly, and not just through traits, so that they could be called without the traits in scope.

No Unit found is not descriptive at all.

We should at least make that error message more clear for cases like:

• "75kg" instead of "75 kg"

Our assumption for parsing a compound quantity is that there will be a space character between the value and the unit