This patch switches to the assert statements provided by Python's unit
test framework to assure the statements are always executed and produce
proper error messages in case of test failures.
Alternatively, the popular pytest could be used for running tests, and it uses assert statements. (It does some smart detection of them to decide what error message to show.)
This patch switches to the assert statements provided by Python's unit test framework to assure the statements are always executed and produce proper error messages in case of test failures.