What a reliable JSON parser test input text sample might be?

I would like to test a function that is meant to be able to parse and process any valid JSON source text.

Is there a sample piece of JSON (featuring all the test-worthy kinds of sub-strings that can occur in valid JSON code) freely available for this purpose perhaps?

I understand that there is quite a number of JSON standards and parser/generator implementations, each defining its own understanding of "valid JSON". What I am interested in is either a set of separate test samples for some commonly met flavours or just a good "real life" kind sample meaning a parser that would crunch it successfully will have no problems with the overwhelming majority of JSON code met in the wild.