if os.path.exists(os.path.join(self.src_dir, "results")):
             shutil.rmtree(os.path.join(self.src_dir, "results"))
         os.chdir(self.src_dir)
-        cmd = ['cnf-testsuite', 'setup', '-l DEBUG']
+        cmd = ['cnf-testsuite', 'setup', '-l', 'debug']
         try:
             output = subprocess.check_output(cmd, stderr=subprocess.STDOUT)
         except subprocess.CalledProcessError as exc:
             return False
         self.__logger.info("%s\n%s", " ".join(cmd), output.decode("utf-8"))
         cmd = ['cnf-testsuite', 'cnf_setup',
-               'cnf-config=cnf-testsuite.yml', '-l DEBUG']
+               'cnf-config=cnf-testsuite.yml', '-l', 'debug']
         try:
             output = subprocess.check_output(cmd, stderr=subprocess.STDOUT)
         except subprocess.CalledProcessError as exc:
     def run_conformance(self, **kwargs):
         """Run CNF Conformance"""
         cmd = ['cnf-testsuite', kwargs.get("tag", self.default_tag),
-               '-l DEBUG']
+               '-l', 'debug']
         output = subprocess.run(
             cmd, stderr=subprocess.STDOUT, stdout=subprocess.PIPE,
             check=False).stdout