Battery load testing is the method evaluating a battery to determine what its capabilities are. New batteries should be load tested at the factory to ensure they were properly assembled and performing at the listed specifications. Older batteries can be load tested to determine how well it is performing and when it is time to replace the battery.
Load testing a battery involves one or more charge and discharge cycles with multimeters attached to the battery and recording various parameters over time. The voltage difference across the battery varies with the amount of energy stored in the battery. By recording and analyzing this data we can interpolate the average performance of each individual cell inside the battery. Different battery chemistries require different methods of testing. Lithium batteries have an internal resistance so they must be tested as a complete system over a period of time in order to gather an useful information on them. The load portion of this test is a component or system of components that can vary the draw or load on the battery. With a known resistance of a circuit and voltage across the battery we are able to measure the current flowing through the test circuit over time and determine how much “life” is left in the rechargeable battery. On average, batteries that perform below 80% of their original capacity are considered old and should be replaced. Below that level the typical performance falls short of what most users expect out of it.
To sum things up, your battery has likely been load tested at least once, and can be tested again if you are unsure of its ability to hold a charge or don’t seem to be getting the range out of it that you expected. Otherwise this is not a test that regularly needs to be performed because every battery only has a limited number of complete charge cycles on it.