tst_conformance fails with Ubuntu 20.04 in qtmqtt

agent:2021/11/17 11:06:24 build.go:394: Config: Using QtTest library 5.15.8, Qt 5.15.8 (x86_64-little_endian-lp64 shared (dynamic) debug build; by GCC 9.3.0), ubuntu 20.04
agent:2021/11/17 11:06:24 build.go:394: QDEBUG : Tst_MqttConformance::initTestCase() Launching broker: "python3" ("/opt/paho_broker/interoperability/startbroker.py", "-c", "/opt/paho_broker/interoperability/localhost_testing.conf")
agent:2021/11/17 11:06:54 build.go:394: QWARN : Tst_MqttConformance::initTestCase() Could not launch MQTT test broker.
agent:2021/11/17 11:06:54 build.go:394: FAIL! : Tst_MqttConformance::initTestCase() No test server given. Please specify MQTT_TEST_BROKER in your environment.
agent:2021/11/17 11:06:54 build.go:394: Loc: [tst_conformance.cpp(81)]
agent:2021/11/17 11:06:54 build.go:394: PASS : Tst_MqttConformance::cleanupTestCase()
agent:2021/11/17 11:06:54 build.go:394: Totals: 1 passed, 1 failed, 0 skipped, 0 blacklisted, 30019ms
agent:2021/11/17 11:06:54 build.go:394: ********* Finished testing of Tst_MqttConformance *********
agent:2021/11/17 11:06:54 build.go:394: make: *** [Makefile:285: check] Error 1
agent:2021/11/17 11:06:54 build.go:445: Process finished with error: exit status 2
agent:2021/11/17 11:07:14 runner.go:251: Re-running tests/auto/conformance with TESTARGS=initTestCase
agent:2021/11/17 11:07:14 build.go:531: [make check -j1] 15m0s 15m0s
agent:2021/11/17 11:07:14 build.go:417: [make check -j1] 15m0s 15m0s false false
agent:2021/11/17 11:07:14 build.go:394: /home/qt/work/qt/qtmqtt/tests/auto/conformance/target_wrapper.sh ./tst_conformance initTestCase -maxwarnings 0
agent:2021/11/17 11:07:14 build.go:394: ********* Start testing of Tst_MqttConformance *********
agent:2021/11/17 11:07:14 build.go:394: Config: Using QtTest library 5.15.8, Qt 5.15.8 (x86_64-little_endian-lp64 shared (dynamic) debug build; by GCC 9.3.0), ubuntu 20.04
agent:2021/11/17 11:07:14 build.go:394: Unknown test function: 'initTestCase'. Possible matches:
agent:2021/11/17 11:07:14 build.go:394: ./tst_conformance -functions
agent:2021/11/17 11:07:14 build.go:394: lists all available test functions.
agent:2021/11/17 11:07:14 build.go:394: make: *** [Makefile:285: check] Error 1