Integration tests are to test scenarios between the client and server.
Since tests create and listen on ports, use pki folders, they must be run one at a time, like this:
cargo test --features integration -- --test-threads=1
Or use the run.sh or run-sanity.sh script.
The X509 token required for some tests is in x509/ and generated like so:
openssl req -x509 -nodes -newkey rsa:4096 -keyout user_private_key.pem -outform der -out user_public_cert.der -days 10000