SummaryThis paper presents a case study of coverage‐based regression testing techniques on a real world industrial system with real regression faults. The study evaluates four common prioritization techniques, a test selection technique, a test suite minimization technique and a hybrid approach that combines selection and minimization. The study also examines the effects of using various coverage criteria on the effectiveness of the studied approaches. The results show that prioritization techniques that are based on additional coverage with finer grained coverage criteria perform significantly better in fault detection rates. The study also reveals that using modification information in prioritization techniques does not significantly enhance fault detection rates. The results show that test selection does not provide significant savings in execution cost (<2%), which might be attributed to the nature of the changes made to the system. Test suite minimization using finer grained coverage criteria could provide significant savings in execution cost (79.5%) while maintaining a fault detection capability level above 70%, thus representing a possible trade‐off. The hybrid technique did not provide a significant improvement over traditional minimization techniques. Copyright © 2015 John Wiley & Sons, Ltd.

Testing the correct behaviour of data processing systems in the presence of faulty data is extremely expensive. The data structures processed by these systems are often complex, with many data fields and multiple constraints among them. Software engineers, in charge of testing these systems, have to handcraft complex data files or databases, while ensuring compliance with the multiple constraints to prevent the generation of trivially invalid inputs. In addition, assessing test results often means analysing complex output and log data. Though many techniques have been proposed to automatically test systems based on models, little exists in the literature to support the testing of systems where the complexity is in the data consumed in input or produced in output, with complex constraints between them. In particular, such systems often need to be tested with the presence of faults in the input data, in order to assess the robustness and behaviour of the system in response to such faults. This paper presents an automated test technique that relies upon six generic mutation operators to automatically generate faulty data. The technique receives two inputs: field data and a data model, i.e. a UML class diagram annotated with stereotypes and OCL constraints. The annotated class diagram is used to tailor the behaviour of the generic mutation operators to the fault model that is assumed for the system under test and the environment in which it is deployed.Empirical results obtained with a large data acquisition system in the satellite domain show that our approach can successfully automate the generation of test suites that achieve slightly better instruction coverage than manual testing based on domain expertise.Further, the technique automates test oracles that, in our 978-1-4799-7125-1/15/$31.00 ©2015 IEEE

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When testing data processing systems, software engineers often use real world data to perform system level testing. However, in the presence of new data requirements software engineers may no longer benefit from having real world data with which to perform testing. Typically, new test inputs complying with the new requirements have to be manually written.We propose an automated model-based approach that combines data modelling and constraint solving to modify existing field data to generate test inputs for testing new data requirements. The approach scales in the presence of complex and structured data, thanks to both the reuse of existing field data and the adoption of an innovative input generation algorithm based on slicing the model into parts.We validated the scalability and effectiveness of the proposed approach using an industrial case study. The empirical study shows that the approach scales in the presence of large amounts of structured and complex data. The approach can produce, within a reasonable time, test input data that is over ten times larger in size than the data generated with constraint solving only. We also demonstrate that the generated test inputs achieve more code coverage than the test cases implemented by experienced software engineers.

&lt;p&gt;La Palma Island (708 km&lt;sup&gt;2&lt;/sup&gt;) is located at the north-west and is one of the youngest (~2.0My) of the Canarian Archipelago. On September 19, 2021, a new volcanic eruption occurred at Cumbre Vieja volcanic system at the southern part of the island, the most active basaltic volcano in the Canaries. The erupting fissure (~1.0 km-length) is characterized by lava effusion, strombolian activity, lava fountaining, ash venting and gas jetting. After 85 days of eruption finished on December 13, 2021. We report herein the results of an intensive soil gas study, focused on non-reactive and/or highly mobile gases such as helium (He) and hydrogen (H&lt;sub&gt;2&lt;/sub&gt;), in Cumbre Vieja. He has unique characteristics as a geochemical tracer: it is chemically inert and radioactively stable, non-biogenic, highly mobile and relatively insoluble in water. H&lt;sub&gt;2&lt;/sub&gt; is one of the most abundant trace species in volcano-hydrothermal systems and is a key participant in many redox reactions occurring in the hydrothermal reservoir gas. Since 2002, soil gas samples were regularly collected at ~40 cm depth using a metallic probe at 600 sites for each survey. He content was analysed by means of a quadrupole mass spectrometer (QMS; Pfeiffer Omnistar 422 and HIDEN QGA) and H&lt;sub&gt;2&lt;/sub&gt; concentrations by a micro-gas chromatograph (microGC; VARIAN CP490). Spatial distribution maps have been constructed following the sequential Gaussian simulation (sGs) procedure to quantify the diffuse He and H&lt;sub&gt;2&lt;/sub&gt; emission from the studied area. The time series of both diffuse He and H&lt;sub&gt;2&lt;/sub&gt; emission show significant increases before and during the occurrence of seismic swarms that took place in the period 2017-2021. During the eruptive period, significant increases in diffuse He and H&lt;sub&gt;2&lt;/sub&gt; emission were also observed with good temporal agreement with the increase of the volcanic tremor. These increases in diffuse He and H&lt;sub&gt;2&lt;/sub&gt; emission preceded the peak of diffuse CO&lt;sub&gt;2&lt;/sub&gt; emission as expected by the characteristics of these gases. The absence of visible volcanic gas emissions (fumaroles, hot springs, etc.) at the surface environment of Cumbre Vieja, makes this type of studies in an essential tool for volcanic surveillance purposes.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

&lt;p&gt;The recent volcanic eruption of Cumbre Vieja, on the island of La Palma, has beenconsidered by many to be the most important and devastating urban eruption of the last 100 years in Europe. After its completion on December 13, 2021, some urban areas not directed damaged by lava flows are affected by strong carbon dioxide (CO&lt;sub&gt;2&lt;/sub&gt;) emissions from the soil. CO&lt;sub&gt;2&lt;/sub&gt; is a toxic gas at high concentration, as well as an asphyxiant gas and may be lethal when present in concentrations higher than 15 V%. The base of the small cliff where the La Bombilla neighborhood is located as well as the basements and garages of numerous buildings in the town of Puerto Naos, seem to represent leaking pathways along which CO&lt;sub&gt;2&lt;/sub&gt; related to the volcanic-hydrothermal activity rises to the surface. In order to assess the hazard represented by the endogenous gas emissions, a scientific observational study was undertaken by means of diffuse CO&lt;sub&gt;2&lt;/sub&gt; and H&lt;sub&gt;2&lt;/sub&gt;S efflux measurements as well as gas sampling from the soil atmosphere at 40cm depth and the measurement of the soil temperature at 15cm and 40cm in 97 points homogeneous distributed at La Bombilla and Puerto Naos, in order to delimit anomalous gas emission zones and to know the emission rates of the measured gases. Also we carried out the installation of a Tunable Diode Laser system to measure continuously the CO&lt;sub&gt;2&lt;/sub&gt; air concentrations in the basement of a building at Puerto Naos and three permanent CO&lt;sub&gt;2&lt;/sub&gt; monitoring stations. Diffuse CO&lt;sub&gt;2&lt;/sub&gt; efflux values measured in the Puerto Naos area were relatively low (between not detected and 24 g m&lt;sup&gt;-2&lt;/sup&gt; d&lt;sup&gt;-1&lt;/sup&gt;). However, in numerous points of the built-up area of Puerto Naos, air CO&lt;sub&gt;2&lt;/sub&gt; concentration values measured both in the street at a height of about 40 cm and in the lower part of several garage doors were generally over 1-2%V, with some sites with values higher than 20%V. The area with the highest CO&lt;sub&gt;2&lt;/sub&gt; diffuse efflux values is located in the La Bombilla neighborhood, reaching values higher than 7 kg m&lt;sup&gt;-2&lt;/sup&gt; d&lt;sup&gt;-1&lt;/sup&gt;. &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C-CO&lt;sub&gt;2&lt;/sub&gt; values of soil gases ranged from -19.2 to -1.7&amp;#8240; vs. VPDB, confirming a volcanic-hydrothermal origin for those samples exhibiting high CO&lt;sub&gt;2&lt;/sub&gt; effluxes and concentration. No H&lt;sub&gt;2&lt;/sub&gt;S effluxes as well as air concentrations were registered. During the survey, many animals were found dead due to high concentrations of CO&lt;sub&gt;2&lt;/sub&gt; and low levels of O&lt;sub&gt;2&lt;/sub&gt; in the air .All these anomalous CO&lt;sub&gt;2&lt;/sub&gt; emissions are not associated to thermal anomalies. Results of this study show that in many sites at La Bombilla and Puerto Naos areas there is a dangerous CO&lt;sub&gt;2&lt;/sub&gt; air concentration that exceeds the hazardous thresholds. These zones should be continuously monitored for gas hazard and the multi-measurement approach adopted in the present study is of paramount importance for decision-making of people's return to their homes.&lt;/p&gt;