Yes, there are two purposes to reach your desire with "Surge test".
One is, as you mentioned, to meet the request of IEC test.
And the other is just to check the electrical quality of the products by themselves.

The first, surge immunity test requests to test the "lightning impulse test"
depended on IEC 61000-4-5, and it tests wheather an electric/electronic products can endure against the lightning or some trouble- it means some kind
of electric impulse that ocationally occures- or not.
And when it comes to IEC 61000-4-5, the test impulse to energize the product-
under-test is determinded in the rule of IEC, as the impulse voltage while
open circuit(PUT unloaded) values to 6.6kV, and the current on a short circuit
must value 3.3kA, as it is said "Combination Wave".