Author Archives : Mario


Testing and Fault Localization Part 2

The Underlying Problem of Fault Localization The underlying problem for fault localization is a phenomenon called confounding (also called confounding bias). Therefore, we must first understand what confounding bias means. In simplest terms, confounding is an unknown causal quantity that is not directly measurable from observed data[1] In other words, an effect is confounded when its cause […]


Testing and Fault Localization

Testing and Fault Localization One of the goals of software testing is to produce evidence that a piece of software works as intended. That evidence might be in the form of hard, deterministic data or even stochastic results that statistically show the correctness of the software system to some degree, among others. However, with modern software […]


Want to be a testing guru? Use reachability graphs (Part 6)

Continuing with our exploration of reachability graphs, the graph below shows another very interesting bug in Chrome’s PDF viewer. The beauty of reachability graphs is that it is remarkably easy to follow the abstract states to recreate bugs, and it is impossible to make mistakes in doing so. Go ahead and follow the abstract states […]

Step 2 of bug recreate for Chrome's PDF Viewer