Recent research has shown a great interest in supporting self-regulated learning (SRL) strategies in online learning. However, there is hardly any study that has investigated how students' self-regulation of behavior could be promoted in online environments for programming learning and assessment, despite the proliferation of automated programming evaluation systems. This study examined the ways our online Distributed Systems Laboratory (DSLab) tried to enhance students' self-regulation of behavior in a real long-term online educational experience. Participants were a sample of 111 university students who performed a programming assignment using DSLab. A customized questionnaire was used to collect data from all students. Our results revealed that DSLab tool managed to enhance students' self-regulation of behavior to a large extent. Moreover, our study explored the correlation between students' cognitive, metacognitive and critical thinking strategy use and their self-regulation of behavior. Since more and more programming course teachers seek to increase students' SRL in general or distributed programming settings, our study provides significant insights into the evolution of automated assessment tools for supporting the development of students' SRL and behavior.