The Proton python system tests execute against the Java or C implementation, using Maven (via this pom) and CMake/CTest respectively. To run the tests against proton-j, execute: mvn test Example of advanced usage (all of the -D flags are optional): mvn test \ -Dproton.pythontest.pattern='proton_tests.transport.ClientTransportTest.*' \ -Dproton.pythontest.invocations=20 \ -Dproton.pythontest.always_colorize=true