[mristin]

Sorry, I did not express myself clearly. For certain functions you can express all the properties in contracts and have them automatically tested.

For other functions, you write some obvious contracts (so that those are also tested in integration tests or end-to-end tests), but since writing all the contracts would be too tedious or unmaintainable, you test these functions additionally using, say, table-driven tests where you specifically test with data points for which you could not write the preconditions or you check the post-conditions manually given the input data. For example, sometimes is easier to generate the input, manually inspect the results and write the expected results in the test table.

> [...] turn contracts into tests [...]

icontract-hypothesis allows you to ghostwrite Hypothesis strategies which you can further refine yourself.