Abstract-We present an algorithm for constructing fitness functions that improve the efficiency of search-based testing when trying to generate branch adequate test data. The algorithm combines symbolic information with dynamic analysis and has two key advantages: It does not require any change in the underlying test data generation technique and it avoids many problems traditionally associated with symbolic execution, in particular the presence of loops. We have evaluated the algorithm on industrial closed source and open source systems using both local and global search-based testing techniques, demonstrating that both are statistically significantly more efficient using our approach. The test for significance was done using a onesided, paired Wilcoxon signed rank test. On average, the local search requires 23.41% and the global search 7.78% fewer fitness evaluations when using a symbolic execution based fitness function generated by the algorithm.

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We present techniques for representing typed abstract syntax trees in the presence of observable recursive structures. The need for this arose from the desire to cope with left-recursion in combinator based parsers. The techniques employed can be used in a much wider setting however, since it enables the inspection and transformation of any program structure, which contains internal references. The hard part of the work is to perform such analyses and transformations in a setting in which the Haskell type checker is still able to statically check the correctness of the program representations, and hence the type correctness of the transformed program.

Advantages of embedded domain-specific languages (EDSLs) are that one does not have to implement a separate type system nor an abstraction mechanism, since these are directly borrowed from the host language. Straightforward implementations of embedded domain-specific languages map the semantics of the embedded language onto a function in the host language. The semantic mappings are usually compositional, i.e. they directly follow the syntax of the embedded language.One of the questions which arises is whether conventional compilation techniques, such as global analysis and resulting transformations, can be applied in the context of EDSLs. The approach we take is that, instead of mapping the embedded language directly onto a function, we first build a representation of the abstract syntax tree of the embedded program fragment. This syntax tree is subsequently analyzed and transformed, and finally mapped onto a function representing its denotational semantics. In this way we achieve an online compilation of the embedded language.We show how to use typed abstract syntax to represent fragments of embedded programs containing variables and binding structures while preserving the idea that the type system of the host language is used to emulate the type system of the embedded language.The tricky issue is how to keep mutually recursive structures well-typed while being transformed. For this we develop an arrow-like library which assists in implementing such analyses and transformations and show its usefulness in describing left-recursion removal of an embedded grammar expressed with parser combinators using the Left-Corner Transform.

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Abstract-Specifications mined from execution traces are largely used to support testing and analysis of software applications with little runtime variability. However, when models are mined from applications that evolve at runtime, the resulting models become quickly obsolete, and thus of little support for any testing and analysis activity.To cope with such systems, mined specifications must be consistently updated every time the software changes. In principle, models can be periodically mined from scratch, but in many cases this solution is too expensive or even impossible.In this paper we describe Revolution, an approach for the automatic evolution of specifications mined by applying state abstraction techniques. Revolution produces models that are continuously updated and thus remain aligned with the actual implementation. Empirical results show that Revolution can suitably address run-time evolving applications.