The tasks which run the "run auth tests" function all depend on "debug-compile-nosasl-openssl", "debug-compile-nosasl-darwinssl", "debug-compile-nosasl-winssl", or special-purpose builds against particular versions of OpenSSL or LibreSSL. In other words, no task runs the auth tests with a driver that's built with GSSAPI / Kerberos support, and so the GSSAPI tests are silently skipped.