develop a program that lets a user play tic$-$tac$-$toe against the computer. The goal is to identify test cases before the code is written $($using the V$-$Model$).$ You want to maximize code coverage by testing as many paths through the logic as possible at the same time as controlling time and expense by designing a minimal set of test cases to give you confidence that the code works.

Rules of the game

The user can choose to play X or O$.$

X always goes first.

Then X and O take turns placing a marker on the board.

The goal is to win by placing three markers $($X$-$X$-$X$)$ or $($O$-$O$-$O$)$ across one row, down one column, or along a diagonal.

The game often ends in a tie when the nine positions are filled but neither X nor O completed a line.

Scope of this exercise

You are engaged in an Agile development process. In this increment, you are focusing on the logic of deciding what move to make. In other words, test the artificial intelligence of a computer playing a game.

Previous increments prepared the board and prototype user interface. You can assume that tests for valid game moves were completed in an earlier increment. For example, assume user or computer don$$t try to play into an occupied square or play an X when it$$s O$$s turn. Similarly, don$$t worry about how the board is represented internally or displayed to the user. Just trust that some $3$x$3$ display is mapped onto an appropriate data structure in the code.

The code you are testing

The logic for computer$$s move is to try the following in order:

a$.$ If you have two pieces in a line and can complete a line by placing the third, put your X or O in the winning cell.

b$.$ If the user has two markers in a line and can complete the line on his$/$her next move, put your marker in the cell that blocks the user from winning.

c$.$ If the middle of the board is free, put a marker there.

d$.$ If at least one corner is free, put a marker in a corner. Choose the corner randomly.

e$.$ Select randomly from any of the unoccupied cells.

Notes: The five rules above simplify the logic, and don$$t always pick the best move. Therefore, it is possible for the user to beat the computer. The user does not have to follow the same rules and make very silly, but legal, moves.

Note: To analyse these properly you should rely on tried and true methods of information processing. For example, you can come up with a shortcut way of referring to conditions a$.-$e$.$ above by naming them respectively:

a$.-$WIN move, b$.-$BLOCK move, c$.-$CENTER move, d$.-$CORNER move and e$.$ SIDE move $($or RANDOM move$)$

The test objective

The test objective is to verify that the program is applying the rules above in all situations. The goal of this exercise is to design functional tests. Your task is to analyse, design and document enough test cases to be confident of the verification testing. Testing every possibly configuration of pieces is virtually impossible, even for a game as simple as tic$-$tac$-$toe.

Your company will outsource your test cases to test specialists who will implement and execute the tests. Testers will compare actual results with expected results and report all deviations as possible defects.

Instructions

Work with one partner. Healthy discussion and an exchange of different views is good. Finding a consensus approach is part of the exercise. Remember, many different solutions may be good.

Create your solution as an MS Word document.

First, decide how many test cases you need and list them. Use a numbered list so that the numbering gives each test case a unique identifier and add a headline$-$style title $($see template below$).$

Test Case Identifier $($ID$)$ Test Case Title

TC$1$ Computer, with X$,$ plays B$2($center$)$

TC$2...$

$......$

TCN $...$

Note: To complete the following second task below, whenever you need to Specify a precondition or a post condition, you can do it via using the template below. Make sure you identify via the subscripts the order of movements. For example, in the template below X of course has started $1$st and his first move was in B$2($notice the Excel notation is used in this depiction$).$ The PC has used C$3$ as its first movement; then the player has put his movement in C$1$ where you see X$2,$ the second movement of player X indicated via X subscript $2$ or X$2.$ Second movement of PC is $02$ placed in cell A$3$ and then the player places in B$3$ its third movement or X$3.$ This can serve as a precondition in the specifications below.

A B C

$1$ X$2$

$2$ X$1$

$3$ O$2$ X$3$ O$1$