Some embodiments provide a program that collects a set of call stack data associated with a set of test cases executed on an application. The program further generates a set of call graphs based on the set of call stack data. Each call graph in the set of call graphs includes a set of nodes representing a set of functions in the application executed in the corresponding test case in the set of test cases. The program also determines, for each call graph in the set of call graphs, a set of short paths and a set of short sequences in the call graph. The program further receives a notification indicating a modification to a function in the application. The program also determines a subset of the set of test cases to test the modification to the function based on the sets of short paths and the sets of short sequences in the set of call graphs.