def run(files, temp_folder, arg=None):
try:<EOL><INDENT>import pytest<EOL><DEDENT>except ImportError:<EOL><INDENT>return NO_PYTEST_MSG<EOL><DEDENT>cmd = "<STR_LIT>"<EOL>output = bash(cmd).value()<EOL>output = output.rstrip().splitlines()<EOL>if '<STR_LIT:error>' in output[-<NUM_LIT:1>] or '<STR_LIT>' in output[-<NUM_LIT:1>]:<EOL><INDENT>return "<STR_LIT>".format(output[-<NUM_LIT:1>])<EOL><DEDENT>
Check tests execution.