Thanks for the link to the book, it's very informative. I suppose there is nothing like testing binary crates in external tests. It's either a lib, or no integration tests. Unless we use std::process::Command;. Thank you for the reply.
Thank you for confirming this explicitly, I searched the half web through to find out how to do integration test on binaries. It's a bit sad that it is just not possible.
Sure, you can do integration tests on binaries, cargo is I believe a good example of an executable that uses a lot of integration testing. Another example is rq. You just have to write tests that call your executable.
If you want to test the functions used in your executable with an "integration test", another approach is to make your crate provide both a library and an executable.