Any new functionality that is implemented should be unit tested. Try to break your code and test every code path that you can.
An example for a unit test can be found [here](https://git.rwth-aachen.de/ita/ITABase/-/blob/feature/piecewisepolynomal_speedup/tests/UnitTest/ITABaseUnitTestPiesewisePolynomials.cpp).
An example for a unit test can be found [here](https://git.rwth-aachen.de/ita/ITABase/-/blob/develop/tests/UnitTest/ITABaseUnitTestPiesewisePolynomials.cpp).