How to make right report from programm components

I'm writing test case execute program on python It's consists of init(config parse,logger declaration),setup(Generator:generates orders and makes sql queries from it; MysqlDBConnector:creating db,table and inserting data(sql queries from Generator) into table) , workflow(Reading tests cases(in sql format) and executing it to Generator orders which in mysql table), report(make report from tests) Generator,MysqlDBConnector,Test,Report - main independent classes. Report is aggregated in Test Problem is that i have some important errors which can occur in these classes methods and i should save this error, rightly stop my class instance executing and display error in report. I'm looking for the best way to save error which can occur in any instance and display it in report. I shouldn't exit program, i need to reach end(report)

uml class diagram