Book Image

Test-Driven Java Development

Book Image

Test-Driven Java Development

Overview of this book

Table of Contents (17 chapters)
Test-Driven Java Development
About the Authors
About the Reviewers
Refactoring Legacy Code – Making it Young Again


Connect4 is a popular, very easy-to-play board game. The rules are limited and simple.


Connect4 is a two-player connection game, in which the players first choose a color and then take turns dropping colored discs from the top into a seven-column, six-row, vertically suspended grid. The pieces fall straight down, occupying the next available space within the column. The objective of the game is to connect four of one's own discs of the same color next to each other vertically, horizontally, or diagonally, before your opponent connects four of theirs.

For further information on the game, visit Wikipedia (


In order to code the two implementations of Connect4, the game rules are transcribed below in the form of requirements. These requirements are the starting point for both the developments. We will go through the code with some explanations and compare both implementations at the end:

  1. The board is composed of seven columns and...