icontract is one implementation of Design by Contract for Python; which is also like Eiffel, which is considered ~the origin of DbC. icontract is fancier than compile-time macros can be. In addition to Invariant checking at runtime, icontract supports inheritance-aware runtime preconditions and postconditions to for example check types and value constraints. Here are the icontract Usage docs:
https://icontract.readthedocs.io/en/latest/usage.html#invari...
For unit testing, there's icontract-hypothesis; with the Preconditions and Postconditions delineated by e.g. decorators, it's possible to generate many of the fuzz tests from the additional Design by Contract structure of the source.
> icontract-hypothesis combines design-by-contract with automatic testing.
> It is an integration between icontract library for design-by-contract and Hypothesis library for property-based testing.
> The result is a powerful combination that allows you to automatically test your code. Instead of writing manually the Hypothesis search strategies for a function, icontract-hypothesis infers them based on the function’s [sic] precondition
For unit testing, there's icontract-hypothesis; with the Preconditions and Postconditions delineated by e.g. decorators, it's possible to generate many of the fuzz tests from the additional Design by Contract structure of the source.
From https://github.com/mristin/icontract-hypothesis :
> icontract-hypothesis combines design-by-contract with automatic testing.
> It is an integration between icontract library for design-by-contract and Hypothesis library for property-based testing.
> The result is a powerful combination that allows you to automatically test your code. Instead of writing manually the Hypothesis search strategies for a function, icontract-hypothesis infers them based on the function’s [sic] precondition