1. A method for detecting defects in an online system, the method comprising: receiving, by one or more processor, a plurality of search conditions regarding a search screen of the online system; generating, by the one or more processor, a plurality of test models having factors based on the plurality of search conditions and levels having one or more of the search conditions; generating, by the one or more processor, a plurality of test cases based on the generated plurality of test models having the factors based on the plurality of search conditions and the levels having one or more of the search conditions; and executing, by the one or more processor, the plurality of test cases on the online system to detect defects in the online system; wherein the receiving comprises receiving at least one non-search conditions from the search screen of a specification document, and the generating comprises generating the plurality of test models having the at least one non-search condition as a factor and values of the non-search condition comprising levels.