Summary: The authors present a Korovkin type theorem on uniform approximation of some subclass of continuous and bounded functions by linear positive operators on the positive semiaxis by using test functions
. As an application of this general result, a simple proof of a corresponding statement for Bleimann, Butzer and Hahn operators [see G. Bleimann, P. L. Butzer
and L. Hahn
, Indag. Math. 42, 255–262 (1980; Zbl 0437.41021
)] has been given.