How can I fully test my SQL tool?

I want to build a tool to extract information from SQLs. How can I test the completeness of my tool, or how can I enumerate all the use cases. Is there a framework or existing examples I can borrow?\

I am using python. I am trying to extract information how a table is being used. Is it used all by itself, or by a join? Which columns are used in join? which columns are used in whereclause. I was sort of trying to build up all the use cases, for example, join two tables, three tables, each column is being used in the selection once, etc.