Scala Tutorial Through Katas: Tennis Game (Easy)

A programming kata is an exercise which helps a programmer hone his skills through practice and repetition.

This article is part of the series "Scala Tutorial Through Katas". Articles are divided into easy, medium and hard. Beginners should start with easy ones and move towards more complicated once they feel more comfortable programming in Scala.

For the complete list of Scala katas and solutions please visit the index page

The article assumes that the reader is familiar with the basic usage of ScalaTest asserts and knows how to run them from his favorite Scala IDE (ours is IntelliJ IDEA with the Scala plugin).

Tests that prove that the solution is correct are displayed below. Recommended way to solve this kata is to write the implementation for the first test, confirm that it passes and move to the next. Once all of the tests pass, the kata can be considered solved.

One possible solution is provided below the tests. Try to solve the kata by yourself first.

Tennis Game

Implement a simple tennis game

Rules:

  • Scores from zero to three points are described as "love", "fifteen", "thirty", and "forty" respectively.
  • If at least three points have been scored by each side and a player has one more point than his opponent, the score of the game is "advantage" for the player in the lead.
  • If at least three points have been scored by each player, and the scores are equal, the score is "deuce".
  • A game is won by the first player to have won at least four points in total and at least two points more than the opponent.

Following is a set of unit tests that can be used to solve this kata in the TDD fashion.

[UNIT TESTS]

Following is the BDD scenario that should be used as acceptance criteria.

[BDD SCENARIO]

Test code can be found in the GitHub TennisGame.scala.

[ONE POSSIBLE SOLUTION]

The solution code can be found in TennisGame.scala solution.

What was your solution? Post it as a comment so that we can compare different ways to solve this kata.

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