Is there any online database for test cases?

When writing a piece of code which implements some specifications you definitely need to write some test cases and test your implementation. The problem is you might not know all the edge cases and intricacies of the domain.

Here is an example, imagine I wanna write a parser for Content-Security-Policy based on the w3 - specification. I don't know and I can't generate all the possible values for a CSP header string to test my parser against.

Is there an online database for all the "common" cases so you can just run your code against?

Of course such a database will be only useful for public, standard and widely-used specifications. I also like to call this crowd-sourced generative tests.