Testing and verification of the LHCb Simulation

Monte-Carlo simulation is a fundamental tool for high-energy physics experiments, from the design phase to data analysis. In recent years its relevance has increased due to the ever growing measurements precision. Accuracy and reliability are essential features in simulation and particularly important in the current phase of the LHCb experiment, where physics analysis and preparation for data taking with the upgraded detector need to be performed at the same time. In this paper we will give an overview of the full chain of tests and procedures implemented for the LHCb Simulation software stack to ensure the quality of its results. The tests comprise simple checks to validate new software contributions in a nightlies system as well as more elaborate checks to probe simple physics and software quantities for performance and regression verifications. Commissioning of a new major version of the simulation software for production implies also validating its impact using a few physics anlayses. A new system for Simulation Data Quality (SimDQ) that is being put in place to help in the first phase of commissioning and for fast verification of all samples produced is also discussed.