Which testing frameworks to use for asp.net websites and why

I use visual studio 2005 and now my team wants me to try my hand at some testing frameworks for asp.net websites.I'm completely new to testing. I want to know what kind of automated testing can I do.Can I test my business logic,Can I test my UI.I just started using NUnit and I am getting a hang of it. For Web UI testing I've tried Nunit asp.S开发者_JAVA技巧omewhere I found about Selenium, which of this is better.Also is there an add-in to test Javascript code with NUnit.Is there an better alternative to NUnit. I kind of find difficult to figure out why should I use this tools.

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One option is to use Watin: http://watin.sourceforge.net/

There is a nice Test Recorder, which allows you to record and save your tests.

The only problem I have had with it is that it doesn't always play well with Cruise Control as it loads a browser engine in the background. If the CI server is running in an environment without the correct browsers installed and enabled, then the tests will fail. In this case we ended up using HtmlUnit, which is a java app that runs on the Cruise Control server.

http://htmlunit.sourceforge.net/