On the contrary; it's quite possible to design automated tests that operate on release artifacts. This is true not only at the integration level (testing the external interfaces of the artifact in a black-box manner), but also at a more granular level; e.g., running lower-level unit tests in your code's dependency structure.
It's true that not all tests which are possible to run in debug configuration can also be run on a release artifact; e.g. if there are test-only interfaces that are compiled out in the release configuration.
I think maybe the source of the confusion in this conversation is perhaps the kind of artifact being tested? For example, if I were developing ffmpeg, to choose an arbitrary example, I would absolutely have tests which operate on the production artifact -- the binary compiled in release mode -- which only exercise public interfaces of the tool; e.g. a test which transcodes file A to file B and asserts correctness in some way. This kind of test should be absolutely achievable both in dev builds as well as when testing the deliverable artifact.
It's true that not all tests which are possible to run in debug configuration can also be run on a release artifact; e.g. if there are test-only interfaces that are compiled out in the release configuration.
I think maybe the source of the confusion in this conversation is perhaps the kind of artifact being tested? For example, if I were developing ffmpeg, to choose an arbitrary example, I would absolutely have tests which operate on the production artifact -- the binary compiled in release mode -- which only exercise public interfaces of the tool; e.g. a test which transcodes file A to file B and asserts correctness in some way. This kind of test should be absolutely achievable both in dev builds as well as when testing the deliverable artifact.