Using exclusively open-source software, we have developed and implemented an online testing system dubbed YStatTest. This system allows instructors to create homework, quizzes, and exams by querying a database containing question templates. A template is selected based on such elements as keywords, categories, and historical difficulty. Numerical values, data, and correct answers for each question template are randomly generated upon exam creation. Thus, although two students may receive identical templates, they will likely differ in placement on the exam and most assuredly in the data and numerical values associated with the question. We discuss the impact this testing system has had upon student learning and highlight future planned development for our software.