It works for me. Can you post your getResource call?
Use the "Insert Code" from the toolbar above, otherwise code gets stripped.
Post your testpost chunk content.
Tricky.
If I remember from my experience with getResources, if there is a problem with the chunk, the snippet returns a huge mass of info about all the relevant resources. If I am correct there, and if you are getting a blank screen, then the problem is not with the chunk but with the snippet call or the snippet itself. So before looking into the more complex alternatives, how about double checking the blindingly obvious, such as:
1. Spelling of getResources (in your initial question there is a mispelling).
2. Whether getResources is actually installed (as opposed to having just been downloaded).
3. Whether the id of the parent resource is actually 3.
4. Whether the parent resource has actually been published (otherwise you need to tell getResources to show hidden resources).
It the output actually shows the raw code of the chunk in a normal page view, it's likely that the chunk's code has been converted to html entities somehow. Are you using TinyMCE to edit the chunk?