DSpot first implementation in the Pharo Smalltalk ecosystem

Pharo Smalltalk

Title: Test amplification in the Pharo Smalltalk Ecosystem
Authors: Mehrdad Abdi, Henrique Rocha and Serge Demeyer, University of Antwerp
Event: International Workshop on Smalltalk Technologies 2019, Cologne 

The STAMP team is glad to announce a brilliant external contribution to DSpot open source test amplification tool, from the University of Antwerp. 

Thanks to Mehrdad Abdi, Henrique Rocha and Serge Demeyer, DSpot is no longer limited to Java applications. The researcher team has successfully replicated the core of DSpot to Smalltalk, developing test amplification in the Pharo environment. The three researchers improved a test suite mutation score, applying DSpot on a simple Bank application with a few methods and test cases. They have learned a lot from there and they are currently fine tuning internal algorithms to scale up to more realistic Smalltalk systems.

Test amplification is the act of strengthening existing unit tests to exercise the boundary conditions of the unit under test. It is an emerging research idea which has been demonstrated to work for Java, relying on the type system to safely transform the code under test. In this paper we report on a feasibility study concerning test amplification in the context of the Smalltalk eco-system. We introduce a proof-of-concept test amplifier named Small-Amp, and discuss the advantages and challenges we encountered while incorporating the tool into the Pharo Smalltalk environment. We demonstrate that by building on top of the Refactoring Browser API, the MuTalk mutation tool, it is feasible to build a test amplifier in Pharo Smalltalk despite the absence of a type system.