10. An information processing system for software debugging, the system comprising: data storage for storing inputs, the inputs comprising: an interface configured for accessing at least a portion of a program exhibiting faulty behavior, a failing input sequence from the at least a portion of the program, a behavioral model of the at least a portion of the program, and mutation operators; a processor configured for performing steps of: executing the failing input sequence stepwise in parallel on both the behavioral model and the at least a portion of the program; validating, after each execution, an expected behavior of the at least a portion of the program by executing test sequences constructed from the behavioral model, wherein the test sequences comprise model states and transitions; performing model mutation using mutation operators, for creating a hypothesis of faulty program behaviors; verifying each faulty program behavior in the hypothesis using the model mutators; and assigning a score to each faulty behavior, wherein the score comprises a percentage of executions of confirming sequences that match the faulty program behavior; and ranking the scores for producing a ranked list of diagnoses, wherein the diagnoses correspond to the mutation operators; and an input/output subsystem for interacting with a user of the system.
10. An information processing system for software debugging, the system comprising: data storage for storing inputs, the inputs comprising: an interface configured for accessing at least a portion of a program exhibiting faulty behavior, a failing input sequence from the at least a portion of the program, a behavioral model of the at least a portion of the program, and mutation operators; a processor configured for performing steps of: executing the failing input sequence stepwise in parallel on both the behavioral model and the at least a portion of the program; validating, after each execution, an expected behavior of the at least a portion of the program by executing test sequences constructed from the behavioral model, wherein the test sequences comprise model states and transitions; performing model mutation using mutation operators, for creating a hypothesis of faulty program behaviors; verifying each faulty program behavior in the hypothesis using the model mutators; and assigning a score to each faulty behavior, wherein the score comprises a percentage of executions of confirming sequences that match the faulty program behavior; and ranking the scores for producing a ranked list of diagnoses, wherein the diagnoses correspond to the mutation operators; and an input/output subsystem for interacting with a user of the system. 17. The system of claim 10 wherein the behavioral model comprises abstract model states and transitions explicitly implemented in the program.