A while ago I said that I may come back and enter detail instructions on how to install simple test on drupal 6 on Windows. I forgot about it, and, of course, I need that information now. So here it is, in its detailed glory, how to do this.
1. Download simple test from this link http://drupal.org/project/simpletest
2. Make sure that you have curl installed. Check whether curl has been installed by looking at your phpinfo() page, or running on the command line php -i . If you don't have it installed, install it. On windows, that means going to your php.ini, and uncommenting the line where it says php_curl.dll and potentially moving php_curl.dll to Windows/system32 More information on this link http://www.php.net/manual/en/curl.installation.php read the 28-Dec-2009 07:17 comment by wixelbomb for more details on it.
3. Run the patch on drupal 6 core. Oh, boy, was this fun 2 months ago.
First, information on applying the patch is given here http://drupal.org/patch/apply If you are using windows, that means that the utility that you need must be run in cygwin http://www.cygwin.com/ or you need http://unxutils.sourceforge.net/ . That is actually not that bad. More information specific to windows on http://drupal.org/node/60179
What ended up being hard to figure out where you should run the patch. The answer to this, for simpletest, is your root drupal directory. Since I don't like to type too much, I copied and pasted D6-core-simpletest.patch to root, and ran the following command in cygwin
patch -p0 < D6-core-simpletest.patch
That should be it. Then you can have fun testing.