Fine, if you are well aware of the aidl's purpose you can get it working in your test application. All that you need is to obtain the xyz.aidl from the correspoding repo. (Whenever you need it -> sync it from the google code repo -> use tortoise svn (win 32 client)). As soon as you sync it, cpy that aidl file along with its package structure (com.android.internal.telephony) and place it in your src file. After adding it there, open eclipse and refresh your project. If it has not been added yet, then perform a clean and make sure the particular interface gets added in your project explorer.
Once that is listed, you can make use of the interface and call the functions directly from the local thread. You can notice the xyz.java file generated in the project explorer.