Simple LTI Test Client
Click here to use the Simple LTI Client. It is a form with sample form-post values. You can either post the values to this server - or post them to your own server. Since the Simple LTI uses simple POST parameters - you can even save the HTML from this form and make your own test form on your computer.
Simple LTI Service EndPoint
You can send launch requests to this URL:
http://simplelti.appspot.com/launch
The shared secret is always secret
You must send post data to the URL according to the developer documentation. This service is written in Python and hosted a Google's free Aplication Engine site. (Thanks Google).
IMS Common Cartridge/SimpleLTI Test Harness
You can play with the IMS Common Cartridge Test Harness where you can upload a common cartridge with a SimpleLTI descriptor and see if its syntax verifies.