如何在旧版本的Bash上测试我的Bash脚本？

I'm working on a Bash library and want to ensure I'm supporting as many environments as possible - including old installations of Bash. My development environment is Bash 4.3, but some of my users may well be running much older versions and presently I have no way to confirm or deny that my library will work for them. In particular I'd like to be compatible with OSX (which still ships with Bash 3.2, AFAIK).I'm working on a Bash library and want to ensur