id summary reporter owner description type status priority milestone component resolution keywords cc merged author reviewer upstream work_issues branch commit dependencies stopgaps
24263 MPolynomialRing_polydict not well tested embray "Something I hit upon in fixing some Python 3 issues is the `sage.rings.polynomial.multi_polynomial_ring` module and the `MPolynomialRing_polydict` class and its associated elements.
This is an example of where Sage's policy of ""every function must have tests"" does not actually guarantee good coverage, as few (if any) of the tests for this class ''explicitly'' use it. Instead many of the tests use the generic `PolynomialRing` constructor, which for many cases ends up returning Singular polynomial rings instead, so the relevant implementation does not end up being well tested (except perhaps indirectly in the cases of parent rings that are not handled by Singular).
It would be better if these tests used the class being tested explicitly, or perhaps if `PolynomialRing` had a better way to explicitly force the implementation to use (the existing `implementation=` keyword doesn't really do much currently except force Singular)." defect new major sage-wishlist algebra N/A