Can i run tests in Unity test runner without creating asmdef files?

I have spent many hours creating asmdef files and moving my scripts in the right places to resolve the dependencies of my assembly definition files. It has worked so far, and now i do not get any compile time errors but I do get some run-time errors which i cant seem to fix. So, I have decided to skip this step and now I am looking for a testing framework which does not require me to create the asmdef files to run the tests. If it is possible using Unity test runner or if there is a third party plugin that does not require me to create assembly definition files, please let me know. Thank you