Picking a research topic for your project can be the hardest part of the research process. These two short videos from NCSU library explain the cyclical nature of selecting a researchable topic, and why you may have trouble finding a "perfect source".
The best way to test your topic is to start researching. Don't be afraid to modify your topic based on the results you get (but be patient, research takes time). Here are some search tips:
This 2:42 video shows how to improve your search using AND/OR/NOT