Detecting Trivial Mutant Equivalences via Compiler Optimisations

Mutation testing realises the idea of fault-based testing, i.e., using artificial defects to guide the testing process. It is used to evaluate the adequacy of test suites and to guide test case generation. It is a potentially powerful form of testing, but it is well-known that its effectiveness is inhibited by the presence of equivalent mutants. We recently studied Trivial Compiler Equivalence (TCE) as a simple, fast and readily applicable technique for identifying equivalent mutants for C programs. In the present work, we augment our findings with further results for the Java programming language. TCE can remove a large portion of all mutants because they are determined to be either equivalent or duplicates of other mutants. In particular, TCE equivalent mutants account for 7.4% and 5.7% of all C and Java mutants, while duplicated mutants account for a further 21% of all C mutants and 5.4% Java mutants, on average. With respect to a benchmark ground truth suite (of known equivalent mutants), approximately 30% (for C) and 54% (for Java) are TCE equivalent. It is unsurprising that results differ between languages, since mutation characteristics are language-dependent. In the case of Java, our new results suggest that TCE may be particularly effective, finding almost half of all equivalent mutants

An agent-based approach for the maintenance of database applications

Database systems lie at the core of almost every modern software application. The interaction between the application source code and the underlying database schema results in a dependency relationship that affects the application’s maintainability by raising a number of additional maintenance issues. To assess this effect and facilitate the maintenance process, a software engineering approach based on software agents is introduced. The distributed and cooperative nature of a software agent system provides the flexibility required to analyze modern multi-tier database applications such as web-based applications. A prototype system, which employs agent architecture in order to satisfy the requirements of the suggested approach, is presented

Employing agents towards database applications testing

Testing multi-tier database applications can be viewed as a distributed task performed at each tier by a number of agents. From this point of view, an agent based approach, originally introduced for the software maintenance of such applications, is extended to provide an effective, intelligent and extensible solution suitable for their testing

Non-english web search: An evaluation of indexing and searching the Greek web

The study reports on a longitudinal and comparative evaluation of Greek language searching on the web. Ten engines, five global (A9, AltaVista, Google, MSN Search, and Yahoo!) and five Greek (Anazitisi, Ano-Kato, Phantis. Trinity, and Visto), were evaluated using (a) navigational queries in 2004 and 2006; and (b) by measuring the freshness of the search engine indices in 2005 and 2006. Homepage finding queries for known Greek organizations were created and searched. Queries included the name of the organization in its Greek and non-Greek, English or transliterated equivalent forms. The organizations represented ten categories: government departments, universities, colleges, travel agencies, museums, media (TV, radio, newspapers), transportation, and banks. The freshness of the indices was evaluated by examining the status of the returned URLs (live versus dead) from the navigational queries, and by identifying if the engines have indexed 32480 active (live) Greek domain URLs. Effectiveness measures included (a) qualitative assessment of how engines handle the Greek language; (b) precision at 10 documents (P@10); (c) mean reciprocal rank (MRR); (d) Navigational Query Discounted Cumulative Gain (NQ-DCG), a new heuristic evaluation measure; (e) response time; (f) the ratio of the dead URL links returned, (g) the presence or absence of URLs and the decay observed over the period of the study. The results report on which of the global and Greek search engines perform best; and if the performance achieved is good enough from a user's perspective. © 2009 Springer Science+Business Media, LLC