Ask HN: What tools do you use to test your website?

That depends. If I'm using a framework I'll try to test the functionality internally first, then validate the form and submit it to make sure it all works. I'd probably automate this with something like urllib2 and beautifulsoup, but that's just me.

For more complicated clientside things you have selenium.

For website security testing I use Nikto and Netsparker to save a bit of time, Skipfish and Burp Professional.

http://browsershots.org

Shows you what your site looks like in different browsers. Extremely useful.

http://browserling.com

This will also let you interact with the website in the given version of a browser.

User acceptance testing: Selenium

Unit testing & load testing: testing framework built into Visual Studio

IE testing: Two or three VMs with different versions of IE installed

Many web frameworks support testing. Are you using a framework? Which one?

Flask

Checkout flask-mail http://flask.pocoo.org/extensions/

There's a page on this in the docs:

http://flask.pocoo.org/docs/testing/