browser plugin to test a site's look when migrating

Question

I'm thinking I need a browser plugin that does the following, and if it doesn't exist, it should. I may as well say FF for now, but it could be any browser.

The problem: when moving a website from one server to another, you need migration testing. It is a pain to click on every link by hand and compare it to the old host. You really need 2 machines or have to constantly thrash your hosts file.

The plugin:

Would allow you to specify an alternate hosts entry for a website. 2 entries would make it clear, one for live, one for test.

The plugin would crawl every link on the site, and render the page in the browser, and save an image of the entire page.

It would switch hosts and repeat, and save images in a second folder. Since the rendering engines match, the images should match. We need to switch hosts (like /etc/hosts) so all absolute links are the same for the site.

Now this could be part of the plugin or external, now that we have 2 folders of identically named images, we run an image-diff program on the whole batch. A quick test would be a bdiff or hash, or we could get more sophisticated and determine how different each image is.

This would save so much time. So can it be done with existing tools, or do I need to go write it?

Answer 1

Have a look at Selenium, it allows you to script interactions with the browser and verify content.

Answer 2

That is overengineered. What kind of website is it? How big? Which framework (PHP, JSP, Rails, etc.)? Why not copy the website onto the new server and grep the code for specific ties to the old server?

Answer 3

I'd concentrate on why you think the site would differ between two servers, and focus on testing those specific cases rather than the whole site. When a site is moved to a new machine the issues are generally very obvious from looking at a couple of pages.

Presumably they are both looking at the same data source, assuming there is a data source, otherwise a folder diff on the two installations would suffice. This being the case, it should be a simple task to identify which areas of the site are likely to be affected by a server migration.

Also, I wouldn't personally trust a machine matching two images to sign off system as ready to go live. There just isn't a substitute for real human testing. Yes it's time consuming, but how important is your site?