The Proton system tests execute against either the Java or the C implementations, based on the chosen profile. To execute, run either "mvn test -P proton-j" or "mvn test -P proton-jni". To reduce the set of Python tests run, set system property proton.pythontest.pattern, for example: mvn test -Dproton.pythontest.pattern='proton_tests.transport.TransportTest.*' The proton-jni profile looks for the JNI jar and native libraries under directory <basedir>/build/proton-c. To override this, run Maven like so: "mvn test -P proton-jni -Dproton-c-build-dir=/path/to/build/dir".