16,219 research outputs found
Input Prioritization for Testing Neural Networks
Deep neural networks (DNNs) are increasingly being adopted for sensing and
control functions in a variety of safety and mission-critical systems such as
self-driving cars, autonomous air vehicles, medical diagnostics, and industrial
robotics. Failures of such systems can lead to loss of life or property, which
necessitates stringent verification and validation for providing high
assurance. Though formal verification approaches are being investigated,
testing remains the primary technique for assessing the dependability of such
systems. Due to the nature of the tasks handled by DNNs, the cost of obtaining
test oracle data---the expected output, a.k.a. label, for a given input---is
high, which significantly impacts the amount and quality of testing that can be
performed. Thus, prioritizing input data for testing DNNs in meaningful ways to
reduce the cost of labeling can go a long way in increasing testing efficacy.
This paper proposes using gauges of the DNN's sentiment derived from the
computation performed by the model, as a means to identify inputs that are
likely to reveal weaknesses. We empirically assessed the efficacy of three such
sentiment measures for prioritization---confidence, uncertainty, and
surprise---and compare their effectiveness in terms of their fault-revealing
capability and retraining effectiveness. The results indicate that sentiment
measures can effectively flag inputs that expose unacceptable DNN behavior. For
MNIST models, the average percentage of inputs correctly flagged ranged from
88% to 94.8%
Search algorithms for regression test case prioritization
Regression testing is an expensive, but important, process. Unfortunately, there may be insufficient resources to allow for the re-execution of all test cases during regression testing. In this situation, test case prioritisation techniques aim to improve the effectiveness of regression testing, by ordering the test cases so that the most beneficial are executed first. Previous work on regression test case prioritisation has focused on Greedy Algorithms. However, it is known that these algorithms may produce sub-optimal results, because they may construct results that denote only local minima within the search space. By contrast, meta-heuristic and evolutionary search algorithms aim to avoid such problems. This paper presents results from an empirical study of the application of several greedy, meta-heuristic and evolutionary search algorithms to six programs, ranging from 374 to 11,148 lines of code for 3 choices of fitness metric. The paper addresses the problems of choice of fitness metric, characterisation of landscape modality and determination of the most suitable search technique to apply. The empirical results replicate previous results concerning Greedy Algorithms. They shed light on the nature of the regression testing search space, indicating that it is multi-modal. The results also show that Genetic Algorithms perform well, although Greedy approaches are surprisingly effective, given the multi-modal nature of the landscape
FairFuzz: Targeting Rare Branches to Rapidly Increase Greybox Fuzz Testing Coverage
In recent years, fuzz testing has proven itself to be one of the most
effective techniques for finding correctness bugs and security vulnerabilities
in practice. One particular fuzz testing tool, American Fuzzy Lop or AFL, has
become popular thanks to its ease-of-use and bug-finding power. However, AFL
remains limited in the depth of program coverage it achieves, in particular
because it does not consider which parts of program inputs should not be
mutated in order to maintain deep program coverage. We propose an approach,
FairFuzz, that helps alleviate this limitation in two key steps. First,
FairFuzz automatically prioritizes inputs exercising rare parts of the program
under test. Second, it automatically adjusts the mutation of inputs so that the
mutated inputs are more likely to exercise these same rare parts of the
program. We conduct evaluation on real-world programs against state-of-the-art
versions of AFL, thoroughly repeating experiments to get good measures of
variability. We find that on certain benchmarks FairFuzz shows significant
coverage increases after 24 hours compared to state-of-the-art versions of AFL,
while on others it achieves high program coverage at a significantly faster
rate
Visualizing test diversity to support test optimisation
Diversity has been used as an effective criteria to optimise test suites for
cost-effective testing. Particularly, diversity-based (alternatively referred
to as similarity-based) techniques have the benefit of being generic and
applicable across different Systems Under Test (SUT), and have been used to
automatically select or prioritise large sets of test cases. However, it is a
challenge to feedback diversity information to developers and testers since
results are typically many-dimensional. Furthermore, the generality of
diversity-based approaches makes it harder to choose when and where to apply
them. In this paper we address these challenges by investigating: i) what are
the trade-off in using different sources of diversity (e.g., diversity of test
requirements or test scripts) to optimise large test suites, and ii) how
visualisation of test diversity data can assist testers for test optimisation
and improvement. We perform a case study on three industrial projects and
present quantitative results on the fault detection capabilities and redundancy
levels of different sets of test cases. Our key result is that test similarity
maps, based on pair-wise diversity calculations, helped industrial
practitioners identify issues with their test repositories and decide on
actions to improve. We conclude that the visualisation of diversity information
can assist testers in their maintenance and optimisation activities
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