In software engineering, testing is a crucial activity that is designed to ensure the quality of program code. For this activity, software teams spend substantial resources constructing test cases to thoroughly assess the correctness of software functionality. What is the proportion of open source projects that include test cases? What is the effect of number of developers on the number of test cases? In this study, we explore open source projects and investigate the correlation between the presence of test cases and various project development characteristics, including the number of lines of code, the size of development teams and the quantity of bug reports. The results show that projects with test cases are bigger in size and projects with bigger team sizes have higher number of test cases. However, surprisingly, number of test cases has a weak correlation with the number of bugs.