de.rwth.swc.coffee4j.engine.characterization.delta

Class ImprovedDeltaDebugging

java.lang.Object

de.rwth.swc.coffee4j.engine.characterization.delta.ImprovedDeltaDebugging

All Implemented Interfaces:

FaultCharacterizationAlgorithm

public class ImprovedDeltaDebugging
extends Object
implements FaultCharacterizationAlgorithm

An implementation of the Improved Delta Debugging algorithm as described in "Improved Delta Debugging Based on Combinatorial Testing". Basically, the algorithm performs a binary search on failed test inputs to discover failure-inducing combinations. This is done in two steps. The Isolation Algorithm computes one value in the test input which is responsible for failure, while the RI algorithm uses this isolation algorithm to find complete failure-inducing combinations. This implementation goes a bit further by allowing the discovery of failure-inducing combinations for multiple test inputs. All failed test inputs are therefore searched test input by test input, except if failure-inducing combinations found for previous test inputs already explain a failure. Then it is assumed that no other combination is present in the test input.

Important Information: -Generates a very predictable amount of test inputs due to binary search -Does not generate many test inputs per failure inducing combination -Does not work well if two failure-inducing combinations are present in one failed test input or if failure-inducing combinations overlap each other. -Does not consider constraints

Constructor Summary

Constructors

Constructor and Description
ImprovedDeltaDebugging(FaultCharacterizationConfiguration configuration) Creates a new Improved Delta Debugging algorithm for the given configuration.

Method Summary

Modifier and Type	Method and Description
List<int[]>	computeFailureInducingCombinations() Computes a list of most likely failure inducing combinations refined from previous calls to FaultCharacterizationAlgorithm.computeNextTestInputs(Map).
List<int[]>	computeNextTestInputs(Map<int[],TestResult> testResults) Refines the internal list of suspicious of faulty combinations.
static FaultCharacterizationAlgorithmFactory	improvedDeltaDebugging()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ImprovedDeltaDebugging

public ImprovedDeltaDebugging(FaultCharacterizationConfiguration configuration)

Creates a new Improved Delta Debugging algorithm for the given configuration. The ConstraintsChecker is ignored.

Parameters:

configuration - the configuration for the algorithm

Method Detail

improvedDeltaDebugging

public static FaultCharacterizationAlgorithmFactory improvedDeltaDebugging()

Returns:

a factory always returning new instances of the Improved Delta Debugging algorithm

computeNextTestInputs

public List<int[]> computeNextTestInputs(Map<int[],TestResult> testResults)

Description copied from interface: FaultCharacterizationAlgorithm

Refines the internal list of suspicious of faulty combinations. If this method is called for the first time, an initial list of suspicious combinations is created. This process may take a while. After the refinement of the list, test inputs are generated. These test inputs should be executed and this method should then be called with the results of these test inputs until no test inputs are returned. Through this process the underlying algorithm can refine and shorten it's list of suspicious combinations over time.

When no combinations are returned any more, FaultCharacterizationAlgorithm.computeFailureInducingCombinations() can be used to compute a final list of most likely faulty combinations.

Specified by:

computeNextTestInputs in interface FaultCharacterizationAlgorithm

Parameters:

testResults - the results of the initial test suite or previous test inputs generated by this method. Must not be null or empty.

Returns:

a list of further test inputs which need to be executed to refine the list of suspicious combinations

computeFailureInducingCombinations

public List<int[]> computeFailureInducingCombinations()

Description copied from interface: FaultCharacterizationAlgorithm

Computes a list of most likely failure inducing combinations refined from previous calls to FaultCharacterizationAlgorithm.computeNextTestInputs(Map). The combinations returned by this method are not guaranteed to be faulty, but it is guaranteed that no test input executed which contained this combination was successful.

Specified by:

computeFailureInducingCombinations in interface FaultCharacterizationAlgorithm

Returns:

a list of faulty combinations. The list may be ranked, depending on the underlying algorithm. If this list is ranked the combinations on positions with smaller indices are more likely to be failure inducing