Test Case Design Exercise
It is suggested to work in teams of two.
You and a partner are developing 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.
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.
Marking: This assignment is marked out of 10.
Due: One member of each team must upload an MS Word document giving your solution to the
corresponding Assignments folder on eCentennial.
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 3x3 display is mapped onto an appropriate data structure in the code.2
COMP311 - Software Testing and Quality
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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.3
COMP311 - Software Testing and Quality
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➢ FIRST:
Decide how many test cases you need and list them in the answers documents Use a numbered
list so that the numbering gives each test case a unique identifier and title.
Test Case Identifier (ID) Test Case Title
TC1 Computer, with X, plays B2 (center)
TC2 ...
... ...
TCN ...
Note: To complete the following second task below of this Lab Assignment, 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 1st and his first move was in B2 (notice the Excel notation is used in this
depiction). The PC has used C3 as its first movement; then the player has put his movement in
C1 where you see X2, the second movement of player X indicated via X subscript 2 or X2. Second
movement of PC is 02 placed in cell A3 and then the player places in B3 its third movement or
X3. This can serve as a precondition in the specifications below.
A B C
1 X2
2 X1
3 O2 X3 O1
➢ SECOND
Write a detailed specification for at least 4 test cases. Use the template given:
• Test case identifier - from your list of test cases.
• Test case title -- from you list of test cases.
• Condition - in this case it is sufficient to specify which of the rules listed above apply. Do
not assume there is a one-to-one relationship between test cases and rules. Some rules may
justify several different tests and other may not need any.
• Precondition - state before computer makes a move. The precondition must be a valid
state that could be reached in a game when the program works correctly.
• Action - trigger that causes the program to do something. For example, the user asking the
computer to make the first move is an action.
• During play, the user's move sets the precondition and the fact the user completes a turn is
the trigger for the computer to take a turn.
• Postcondition - expected state after the computer has moved If more than one correct
outcome may be possible, show them all.4
COMP311 - Software Testing and Quality
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Do not forget that the computer may be playing as X or as O, and you are testing the movements
of computer (not the player - the player can move as they please), so they must obey conditions
a.-e.
See the template below for an example. While the following example can be in your list in Task
One, please do not use this example in Task Two

 

 

 

 

 

 

 

 

 

 

 

 

 

1. Test Case list

 

Test Case Identifier (ID)	Test Case Title

 

 

 

 

 

 

 

 

 

 

 

 

1. Test DESIGN:

 

 

Test Case Identifier

TC₁

Test Case Title

Condition

Precondition

 

	A	B	C
1
2
3

 

 

Action

Postcondition

 

	A	B	C
1
2		X1
3

 

 

 

Test Case Identifier

Test Case Title

Condition

Precondition

 

	A	B	C
1
2
3

 

 

Action

Postcondition

 

	A	B	C
1
2
3

 

 

 

 

 

Test Case Identifier

Test Case Title

Condition

Precondition

 

	A	B	C
1
2
3

 

 

Action

Postcondition

 

	A	B	C
1
2
3

 

 

 

Test Case Identifier

Test Case Title

Condition

Precondition

 

	A	B	C
1
2
3

 

 

Action

Postcondition

 

	A	B	C
1
2
3

 

 

 

 

 

Test Case Identifier

Test Case Title

Condition

Precondition

 

	A	B	C
1
2
3

 

 

Action

Postcondition

 

	A	B	C
1
2
3

 

 

 

Test Case Identifier

Test Case Title

Condition

Precondition

 

	A	B	C
1
2
3

 

 

Action

Postcondition

 

	A	B	C
1
2
3