What is your problem in undergoing the test, which is in your own interest and in the interest of students who come in contact with you in the course of your teaching. I am sure College isn't asking you to get tested and bring certificate every day!
If it's a casual entry into a shop or mall etc for limited time of say half an hour or so, you can be given access with checking your temparature with the device after you wash your hands with Sanitiser and your wearing a correct mask properly.
You are entering the College to teach, interact with students and be with students and colleagues for considerable time extending to several hours. Therefore, your Employer asking you to get tested is very reasonable and so please co-operate with them.
If you want to take a stand on your so called rights, kindly realise that, students and staff too have their right to be healthy and not to be infected by somebody who happens to be one of them and thereby demand everybody is tested negative and then only gain entry.