Effective test program development relies heavily on the reuse of existing and verified code, typically organized in separate libraries linked to the main program. Git Submodules, a powerful feature of Git, provide a solution for incorporating external repositories into a main repository while ensuring secure dependency management and version tracking. This paper presents a way of utilizing Git Submodules to integrate code libraries into a test program. The modular structure offered by submodules enables independent development and versioning of each individual submodule. Furthermore, the paper introduces Visual Studio Code as an ideal tool for managing Git repositories, as it provides intuitive integration also for Git Submodules. Its user-friendly interface streamlines the process of working with submodules, offering a convenient and efficient workflow. By adopting Git Submodules and leveraging the capabilities of Visual Studio Code, test program developers can optimize code reuse, simplify dependency management, and enhance collaboration within their projects. This paper is intended to be a basic guideline for developers starting to use Git Submodules in their test program development processes.