Provide a basic test file for every module

[trir262]

With the new test layout, a file per function can be created, containing all tests for any given function. I have created a first draft for these test files.

Expected Behavior

N/A

Current Behavior

N/A

Possible Solution

N/A

Steps to Reproduce (for bugs)

N/A

Context

N/A

Your Environment

N/A