Valéria Lelli

Arnaud Blouin, Valéria Lelli, Benoit Baudry et al.

User Interfaces (UIs) intensively rely on event-driven programming: widgets send UI events, which capture users' interactions, to dedicated objects called controllers. Controllers use several UI listeners that handle these events to produce UI commands. First, we reveal the presence of design smells in the code that describes and controls UIs. Second, we demonstrate that specific code analyses are necessary to analyze and refactor UI code, because of its coupling with the rest of the code. We conducted an empirical study on four large Java Swing and SWT open-source software systems. We study to what extent the number of UI commands that a UI listener can produce has an impact on the change- and fault-proneness of the UI listener code. We develop a static code analysis for detecting UI commands in the code. We identify a new type of design smell, called Blob Listener that characterizes UI listeners that can produce more than two UI commands. We propose a systematic static code analysis procedure that searches for Blob Listeners that we implement in InspectorGuidget. We conducted experiments on the four software systems for which we manually identified 53 instances of Blob Listener. InspectorGuidget successfully detected 52 Blob Listeners out of 53. The results exhibit a precision of 81.25% and a recall of 98.11%. We then developed a semi-automatically and behavior-preserving refactoring process to remove Blob Listeners. 49.06% of the 53 Blob Listeners were automatically refactored. Patches for JabRef, and FreeCol have been accepted and merged. Discussions with developers of the four software systems assess the relevance of the Blob Listener. This work shows that UI code also suffers from design smells that have to be identified and characterized. We argue that studies have to be conducted to find other UI design smells and tools that analyze UI code must be developed.

Valéria Lelli, Arnaud Blouin, Benoit Baudry et al.

Graphical User Interfaces (GUIs) intensively rely on event-driven programming: widgets send GUI events, which capture users' interactions, to dedicated objects called controllers. Controllers implement several GUI listeners that handle these events to produce GUI commands. In this work, we conducted an empirical study on 13 large Java Swing open-source software systems. We study to what extent the number of GUI commands that a GUI listener can produce has an impact on the change-and fault-proneness of the GUI listener code. We identify a new type of design smell, called Blob listener that characterizes GUI listeners that can produce more than two GUI commands. We show that 21 % of the analyzed GUI controllers are Blob listeners. We propose a systematic static code analysis procedure that searches for Blob listener that we implement in InspectorGuidget. We conducted experiments on six software systems for which we manually identified 37 instances of Blob listener. InspectorGuidget successfully detected 36 Blob listeners out of 37. The results exhibit a precision of 97.37 % and a recall of 97.59 %. Finally, we propose coding practices to avoid the use of Blob listeners.

Valéria Lelli, Arnaud Blouin, Benoit Baudry

Graphical user interfaces (GUIs) are integral parts of software systems that require interactions from their users. Software testers have paid special attention to GUI testing in the last decade, and have devised techniques that are effective in finding several kinds of GUI errors. However, the introduction of new types of interactions in GUIs (e.g., direct manipulation) presents new kinds of errors that are not targeted by current testing techniques. We believe that to advance GUI testing, the community needs a comprehensive and high level GUI fault model, which incorporates all types of interactions. The work detailed in this paper establishes 4 contributions: 1) A GUI fault model designed to identify and classify GUI faults. 2) An empirical analysis for assessing the relevance of the proposed fault model against failures found in real GUIs. 3) An empirical assessment of two GUI testing tools (i.e. GUITAR and Jubula) against those failures. 4) GUI mutants we've developed according to our fault model. These mutants are freely available and can be reused by developers for benchmarking their GUI testing tools.