I am puzzled, What exactly is the difference between diaelectric test and insulation test.
Some says it the same, but others says it's because one applied power to perform the test the latter don't.
And some says both are using power but one is using AC power and the other using Dc power.
There is so many version, can anyone out there set the record straight once and for all.

Depends on the context the words are used, and sometimes depending on the personnel or the area involved.

Dielectric testing is also called Hi-Pot testing, using a test set that applies a very high voltage into a cable or device to be tested, and measures the milliamps that flow through the insulation.

Another test is called Megger, which applies a much lower voltage into the cable or device, and measures the actual resistance in megohoms.

I have included a couple of articles from CE magazine (Compliance Engineering) that offers a detailed explanation of both methods:
http://www.ce-mag.com/archive/02/Spring/gray.html

http://www.ce-mag.com/archive/01/Spring/Ahmadi.html

We use both methods, primarily Hi-Pot testing on Medium and High voltage cables (above 600 Volts), and Megger testing on low voltage cables (600 Volt and below) Hi-Pot testing can be destructive due to the high voltages used, and Megger is considered as Non-destructive.