Limited Unit Test Coverage for `ECCs/QECCs`

[Fe-r-oz]

The package functions perform correctly for existing test cases which are well-defined based on various properties of the codes and existing pedagogical examples taken from literature, but they have not been thoroughly unit tested to confirm their correctness across a broad range of inputs/scenarios/cases. This leaves room for unnoticed bugs, particularly as code complexity increases for some fancy QECCs.

This will require some literature review on the code constructions, adding more tests and improving existing tests. There are a plenty of comments in the tests section to get started with.