"Future-Proofing" Tedana

For tedana to expand, more extensive test cases are needed. A new contributor could have introduced an unknown bug into the codebase, but without extensive testing, there is no way to find out until a code review (and even then, it may slip through!) It would be wise to have vast and wide-ranging tests that catch the bug for the contributor!

For this project, I will write detailed unit test cases for the tedana codebase, hitting as many lines as I can while testing! I will also make changes to the functions themselves to type check the input parameters!