[marc_abonce]

> The TH3 test harness is a set of proprietary tests [...]

> The dbsqlfuzz engine is a proprietary fuzz tester.

It's interesting that an open-source (actually public domain) software uses some proprietary tests. It never occurred to me that this was a possibility, though in retrospective it's obviously possible as long as the tests are not part of the release.

Could this be an alternative business model for "almost-open-source" projects? Similar to open-core, but in this case the project would easy to copy (open features), hard to modify (closed tests).

[blackoil]

Many times these test suites are more valuable than code itself, particularly in legacy software. Trying to find and document thousands of edge cases a software like Excel must have is more difficult than implementing them.

[hgs3]

> It never occurred to me that this was a possibility

Yes, it's viable. I do it for my companies projects in addition to dual-licensing under the GPL. See "The unit tests and Unicode data generators are not public. Access to them is granted exclusively to commercial licensees." [1].

[1] https://github.com/railgunlabs/unicorn?tab=readme-ov-file#li...