1. A computerized method comprising: receiving a parameterized unit test, wherein the parameterized unit test accepts a plurality of input parameters and comprises a series of program statements and one or more assertions verifying program behavior; creating a graph comprising nodes that represent respective constraints on symbolic inputs to the parameterized unit test; symbolically executing, in a computer, the parameterized unit test of an implementation under test to identify a plurality of paths of constraints in the graph as respective path conditions, wherein symbolically executing the parameterized unit test comprises (a)-(b): (a) assigning symbolic input variables to parameters of the parameterized unit test and performing operations on symbolic values; and (b) for a given path of constraints in the graph, adding the constraints in the given path to a respective path condition, wherein the respective path condition is expressed in terms of the symbolic input variables; responsive to encountering the one or more assertions in the parameterized unit test, generating universally quantified formulas from the parameterized unit test, wherein the universally quantified formulas symbolically summarize methods of the parameterized unit test, state that a condition of a given assertion must hold under an aggregated path condition at a time of the given assertion, and comprise a behavioral purity axiom that requires that an intensional heap before execution of the parameterized unit test and the intensional heap after execution of the parameterized unit test be equal; and responsive to encountering an indication that behavioral summaries are to be used, re-using the universally quantified formulas in a symbolic execution.