Just to get some context for my question, I started at a new SME in the UK earlier in the year. I was employed as a PHP developer, but I am Scrum certified and have worked for large and small companies; so alongside moving the company to Agile processes, I've been asked to propose and head QA, automation, testing and releases. Outside of web development, I have no first-hand experience with any of those processes.
Because of this, a bespoke and very light weight request/response PHP framework has been developed in house. The purpose is to migrate the old HTML websites to run in this new framework, with the obvious advantage that pages can be partially templated etc.
What I need to know
I need a way to prove that the HTML served by our framework matches the corresponding HTML source on the live website, and where the differences are (if any exist). We can do this manually (but that's going to take time away from development one way or another).
Is there an automation tool that will compare one webpage (example dev page at https://test.example.com/my-page.html) against another (example corresponding live page at https://example.com/my-page.html) and detail where the HTML source is different? I'm sure that I can write a PHP script which will do this, but if there's something out of the box that'll do the same job then that's saved [expensive] dev time.