information i found so far (probably not all). Not sure if it contains all information necessary to start writing a guide on 'how to test the blockchain'.

https://bitcointalk.org/index.php?topic=117487.0
https://simpleprogrammer.com/testing-blockchain-applications/
https://www.capgemini.com/2017/01/testing-of-smart-contracts-in-the-blockchain-world/
https://blog.gurock.com/testing-blockchain-apps/
https://hackernoon.com/beginners-guide-to-blockchain-explaining-it-to-a-5-years-old-772caac6ae97
https://hackernoon.com/beginners-guide-to-blockchain-explaining-it-to-a-6-year-old-86afa54a5fa8
https://www.pymnts.com/news/b2b-payments/2018/qualitest-blockchain-software-security/
https://www.verdict.co.uk/airline-industry-blockchain-use/
https://www.a1qa.com/blog/specifics-of-testing-blockchain-based-apps/
https://jaxenter.com/ins-outs-testing-blockchain-apps-146447.html