Constructor test
Initial tests for the method Sum
Successful test of Sum method
Added validation test
Failure of validation test
Success of validation test
Test failure of validation test for valid input
Test method name changes
Test Valid inputs
Refactored main method

Now has separate validation method
Failed expected result for main method

Oh no, I've bug in my code!!!

Repair for loop condition...
Fixed a bug!

Corrected the condition in for loop!
Refactored main method

Added the method IsDivisableBy3Or5
Refactored variable name

Now the for variable is named current (used to be i)
Added a new test case
Added a new test case