How Good Are My Tests?

Background: Test quality is a prerequisite for achieving production system quality. While the concept of quality is multidimensional, most of the effort in testing context hasbeen channelled towards measuring test effectiveness. Objective: While effectiveness of tests is certainly important, we aim to identify a core list of testing principles that also address other quality facets of testing, and to discuss how they can be quantified as indicators of test quality. Method: We have conducted a two-day workshop with our industry partners to come up with a list of relevant principles and best practices expected to result in high quality tests. We then utilised our academic and industrial training materials together with recommendations in practitioner oriented testing books to refine the list. We surveyed existing literature for potential metrics to quantify identified principles. Results: We have identified a list of 15 testing principles to capture the essence of testing goals and best practices from quality perspective. Eight principles do not map toexisting test smells and we propose metrics for six of those. Further, we have identified additional potential metrics for the seven principles that partially map to test smells. Conclusion: We provide a core list of testing principles along with a discussion of possible ways to quantify them for assessing goodness of tests. We believe that our work would be useful for practitioners in assessing the quality of their tests from multiple perspectives including but not limited to maintainability, comprehension and simplicity

The Jinx on the NASA software defect data sets

Background: The NASA datasets have previously been used extensively in studies of software defects. In 2013 Shepperd et al. presented an essential set of rules for removing erroneous data from the NASA datasets making this data more reliable to use. Objective: We have now found additional rules necessary for removing problematic data which were not identified by Shepperd et al. Results: In this paper, we demonstrate the level of erroneous data still present even after cleaning using Shepperd et al.'s rules and apply our new rules to remove this erroneous data. Conclusion: Even after systematic data cleaning of the NASA MDP datasets, we found new erroneous data. Data quality should always be explicitly considered by researchers before use

Software defect prediction: do different classifiers find the same defects?

Open Access: This article is distributed under the terms of the Creative Commons Attribution 4.0 International License CC BY 4.0 (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.During the last 10 years, hundreds of different defect prediction models have been published. The performance of the classifiers used in these models is reported to be similar with models rarely performing above the predictive performance ceiling of about 80% recall. We investigate the individual defects that four classifiers predict and analyse the level of prediction uncertainty produced by these classifiers. We perform a sensitivity analysis to compare the performance of Random Forest, Naïve Bayes, RPart and SVM classifiers when predicting defects in NASA, open source and commercial datasets. The defect predictions that each classifier makes is captured in a confusion matrix and the prediction uncertainty of each classifier is compared. Despite similar predictive performance values for these four classifiers, each detects different sets of defects. Some classifiers are more consistent in predicting defects than others. Our results confirm that a unique subset of defects can be detected by specific classifiers. However, while some classifiers are consistent in the predictions they make, other classifiers vary in their predictions. Given our results, we conclude that classifier ensembles with decision-making strategies not based on majority voting are likely to perform best in defect prediction.Peer reviewedFinal Published versio

Life on the Ottoman Border: Essays in Honour of Nenad Moačanin

The articles written by friends, colleagues, former students, and one current doctoral student collected in this celebratory volume dedicated to the doyen of Ottoman studies in Croatia, Professor Nenad Moačanin, are divided into three main chapters entitled “Ottoman Bosnia, Turkish Croatia, and Turkey in Europe,” “Distant Borders and Regions,” and “Glimpses Beyond the Ottoman Border: Habsburg Croatia and the Republic of Dubrovnik.” The first section consists of the articles predominantly dedicated to the main fields of interests of Nenad Moačanin, namely social and economic history of the Ottoman Empire, with special focus on Ottoman Bosnia, the Balkans and Central Europe, as well as the Ottoman borderland in Croatia. The second section entitled “Distant Borders and Regions” brings three articles which are geographically remote from the Western Balkans and Central Europe, such as Crimea, Syria, and Palestine, but nevertheless fit well into the conception of the volume by offering a possibility for comparison of distant regions. The third section “Glimpses Beyond the Ottoman Border: Habsburg Croatia and the Republic of Dubrovnik” contains five articles which provide an important insight into the situation on “the other side.” The volume also includes a biographical overview of Professor Moačanin’s scientific and educational career at the beginning, and the bibliography at the end of the volume .The articles written by friends, colleagues, former students, and one current doctoral student collected in this celebratory volume dedicated to the doyen of Ottoman studies in Croatia, Professor Nenad Moačanin, are divided into three main chapters entitled “Ottoman Bosnia, Turkish Croatia, and Turkey in Europe,” “Distant Borders and Regions,” and “Glimpses Beyond the Ottoman Border: Habsburg Croatia and the Republic of Dubrovnik.” The first section consists of the articles predominantly dedicated to the main fields of interests of Nenad Moačanin, namely social and economic history of the Ottoman Empire, with special focus on Ottoman Bosnia, the Balkans and Central Europe, as well as the Ottoman borderland in Croatia. The second section entitled “Distant Borders and Regions” brings three articles which are geographically remote from the Western Balkans and Central Europe, such as Crimea, Syria, and Palestine, but nevertheless fit well into the conception of the volume by offering a possibility for comparison of distant regions. The third section “Glimpses Beyond the Ottoman Border: Habsburg Croatia and the Republic of Dubrovnik” contains five articles which provide an important insight into the situation on “the other side.” The volume also includes a biographical overview of Professor Moačanin’s scientific and educational career at the beginning, and the bibliography at the end of the volume

Life on the Ottoman Border: Essays in Honour of Nenad Moačanin

The articles written by friends, colleagues, former students, and one current doctoral student collected in this celebratory volume dedicated to the doyen of Ottoman studies in Croatia, Professor Nenad Moačanin, are divided into three main chapters entitled “Ottoman Bosnia, Turkish Croatia, and Turkey in Europe,” “Distant Borders and Regions,” and “Glimpses Beyond the Ottoman Border: Habsburg Croatia and the Republic of Dubrovnik.” The first section consists of the articles predominantly dedicated to the main fields of interests of Nenad Moačanin, namely social and economic history of the Ottoman Empire, with special focus on Ottoman Bosnia, the Balkans and Central Europe, as well as the Ottoman borderland in Croatia. The second section entitled “Distant Borders and Regions” brings three articles which are geographically remote from the Western Balkans and Central Europe, such as Crimea, Syria, and Palestine, but nevertheless fit well into the conception of the volume by offering a possibility for comparison of distant regions. The third section “Glimpses Beyond the Ottoman Border: Habsburg Croatia and the Republic of Dubrovnik” contains five articles which provide an important insight into the situation on “the other side.” The volume also includes a biographical overview of Professor Moačanin’s scientific and educational career at the beginning, and the bibliography at the end of the volume .The articles written by friends, colleagues, former students, and one current doctoral student collected in this celebratory volume dedicated to the doyen of Ottoman studies in Croatia, Professor Nenad Moačanin, are divided into three main chapters entitled “Ottoman Bosnia, Turkish Croatia, and Turkey in Europe,” “Distant Borders and Regions,” and “Glimpses Beyond the Ottoman Border: Habsburg Croatia and the Republic of Dubrovnik.” The first section consists of the articles predominantly dedicated to the main fields of interests of Nenad Moačanin, namely social and economic history of the Ottoman Empire, with special focus on Ottoman Bosnia, the Balkans and Central Europe, as well as the Ottoman borderland in Croatia. The second section entitled “Distant Borders and Regions” brings three articles which are geographically remote from the Western Balkans and Central Europe, such as Crimea, Syria, and Palestine, but nevertheless fit well into the conception of the volume by offering a possibility for comparison of distant regions. The third section “Glimpses Beyond the Ottoman Border: Habsburg Croatia and the Republic of Dubrovnik” contains five articles which provide an important insight into the situation on “the other side.” The volume also includes a biographical overview of Professor Moačanin’s scientific and educational career at the beginning, and the bibliography at the end of the volume

Different classifiers find different defects although with different level of consistency

BACKGROUND - During the last 10 years hundreds of different defect prediction models have been published. The performance of the classifiers used in these models is reported to be similar with models rarely performing above the predictive performance ceiling of about 80% recall. OBJECTIVE - We investigate the individual defects that four classifiers predict and analyse the level of prediction uncertainty produced by these classifiers. METHOD - We perform a sensitivity analysis to compare the performance of Random Forest, Naïve Bayes, RPart and SVM classifiers when predicting defects in 12 NASA data sets. The defect predictions that each classifier makes is captured in a confusion matrix and the prediction uncertainty is compared against different classifiers. RESULTS - Despite similar predictive performance values for these four classifiers, each detects different sets of defects. Some classifiers are more consistent in predicting defects than others. CONCLUSIONS - Our results confirm that a unique sub-set of defects can be detected by specific classifiers. However, while some classifiers are consistent in the predictions they make, other classifiers vary in their predictions. Classifier ensembles with decision making strategies not based on majority voting are likely to perform best