The following scenario applies to all three questions below. Suppose you are building a 70s-style game like Breakout (trivia: Steve Wozniak and Steve Jobs were two of the original designers of this game back in the day). The objective of the game is to move a player horizontally at the bottom of the display to hit a puck. The puck will bounce off the player, and the edges of the screen, at a particular velocity. The player should attempt to hit the puck in a way so that it collides with bricks at the top of the screen. There will be multiple rows of bricks (usually you start a game with around 8 rows, but as the game progresses and it gets harder, more rows can be added). Each collision between puck and bricks will destroy one or more bricks, depending on velocity and position. Once all bricks have been destroyed, the round is successfully finished (and a new round begins). If the player misses the puck and it drops off the bottom of the display, a puck is lost. The player has three pucks, and once all three have been lost, the player’s game is over.

Consider the class Velocity, used in Breakout, whose class interface is specified below. Velocity is used to track the velocity (speed + direction) of the puck that is currently in play. A velocity object represents the movement of a puck (or more generally, a sprite) on a playfield based on attributes of speed (expressed in playfield units per unit time) and a direction (expressed as an angle in degrees; 0 represents east or right; 90 designates north or up; and so on). The speed attribute is broken up into two components: speedX (speed in the x direction, i.e., left-right) and speedY (speed in the up-down direction). While the speed attribute is always non-negative, the components of a velocity’s speed can be negative. The value of speedX is negative if a velocity’s direction is heading left. The value of speedY is negative if the direction is down. Speed and Direction are abstract types that ultimately are defined as integer values.

public class Velocity {
private Speed speed, speedX, speedY;
private Direction direction;

public Velocity(); //constructor
public Velocity(Speed speed, Direction direction); //constructor

public Speed getSpeed();
public Speed getSpeedX(); // get speed in X direction
public Speed getSpeedY(); // get speed in Y direction
public Direction getDirection();

public void setSpeed(Speed speed);
public void setDirection(Direction direction);
public void reverse(); // reverse the direction of the puck!
public void reverseX(); // reverse the direction of the puck in x-axis
public void reverseY();

1. [10 marks] Using a table, specify a test plan for the Velocity class. Your test plan should state the following: