A code kata is an exercise in programming which helps a programmer hone their skills through practice and repetition.
https://en.wikipedia.org/wiki/Kata_(programming)
Test-driven development (TDD) is a software development process that relies on the repetition of a very short development cycle: first the developer writes an (initially failing) automated test case that defines a desired improvement or new function, then produces the minimum amount of code to pass that test, and finally refactors the new code to acceptable standards.
https://en.wikipedia.org/wiki/Test-driven_development
The tennis scoring code kata is an exercise to determine the correct call by an umpire for a specific tennis game score.
Use the following as examples of what the calls should be.
0 = Love
1-0 => Fifteen-Love
2-0 => Thirty-Love
3-0 => Forty-Love
4-0 => Winner
4-3 => Advantage Player
4-4 => Deuce
2-2 => Thirty-All
1-1 => Fifteen-All