This project is made for illustrate how TDD works. Sample was taken from here

Project has 7 steps which represented in brunches. Follow from 1 to 7. Each branch will have changes made in order to feet requirements by using TDD.

• Create a simple String calculator with a method int Add(string numbers)
• The method can take 0, 1 or 2 numbers, and will return their sum (for an empty string it will return 0) for example “” or “1” or “1,2”
• Allow the Add method to handle an unknown amount of numbers
• Allow the Add method to handle new lines between numbers (instead of commas).
• The following input is ok: “1\n2,3” (will equal 6)
• Support different delimiters. To change a delimiter, the beginning of the string will contain a separate line that looks like this: “//[delimiter]\n[numbers…]” for example “//;\n1;2” should return three where the default delimiter is ‘;’ .
• The first line is optional.
• All existing scenarios should still be supported
• Calling Add with a negative number will throw an exception “negatives not allowed” – and the negative that was passed. If there are multiple negatives, show all of them in the exception message stop here if you are a beginner.