Specify CMake Minimum Version in Test Modules

[threeal]

This issue suggests specifying the minimum required version of CMake in the test modules by using the cmake_minimum_required function. This change is proposed because the test modules will essentially be invoked as scripts independent from the root CMakeLists.txt. Therefore, it is suggested to specify the minimum required version of CMake in the test modules to maintain consistent behavior by disallowing older CMake policies.