One of the key factors for the successful development of a physics Monte-Carlo is the ability to properly organize regression testing and validation. Geant4, a world-standard toolkit for HEP detector simulation, is one such example that requires thorough validation. The CERN/SFT group, which contributes to the development, testing, deployment and support of the toolkit, is also responsible for the monthly validation of the development releases of Geant4, based on a set of community-developed tests.
In this talk we present the web application "geant-val" developed specifically to analyse and visualise results whilst comparing them between different Geant4 releases. The application is written using the Node.js and Angular frameworks, and uses PostgreSQL for storing test results. The output is visualised using ROOT and JSROOT. In addition to a pure visual comparison, we perform different statistical tests (chi-square, Kolmogorov-Smirnov etc) on the client side using HTML5 Web Workers.
The "geant-val" application has been demonstrated to be a robust tool for the regression testing and validation of the Geant4 toolkit. The generic design is such that it can be applied to compare any histograms no matter from which Monte-Carlo code/generator the data were produced.