Software Verification, Validation and Testing

The Implementation of
Control Flow Graph
and Test Cases
submitted in partial fulfillment of the requirements
for software verification, validation and testing of
Master of Engineering
In
Software Engineering
Submitted to: Submitted by:
Mr. Ajay Kumar Sukhpal Singh
AP (CSED) 801131024
Computer Science & Engineering Department
THAPAR UNIVERSITY, PATIALA
(Formerly known as Thapar Institute of Engg. & Tech.)
(Established under section 3 of UGC Act, 1956 vide notification # F-12/84-U.3 of Government of India)

TO WHOM IT MAY CONCERN
7th May, 2012
I hereby declare that, Sukhpal Singh, Roll No. 801131024 of Thapar University Patiala, have
undergone a project from 2nd January to 7th May, 2012. I worked on ‘Implementation of
Control Flow Graph’ project during the software verification, validation and testing lab under
the supervision of project guide Mr. Ajay Kumar. It is my heartfelt pleasure and deepest sense
of gratitude to offer my humble and sincere thanks towards Mr. Ajay Kumar, my project guide,
for his valuable and constant assistance, cooperation, and incisive criticism in my work towards
my goal.
Student’s Signatures Signature of Project Guide

TABLE OF CONTENTS
1. Control Flow…………………………………………………………….1
2. Control Flow Graph…………………………………………………….1
3. Control Flow Diagram…………………………………………………..1
4. Browsing…………………………………………………………………2
5. Test Cases………………………………………………………………..5
5.1 For Loop……………………………………………………………..5
5.2 If………………………………………………………………………7
5.3 If-else-for……………………………………………………………..9
5.4 Nested if……………………………………………………………..11
5.5 If-for…………………………………………………………………13
5.6 If with two conditions……………………………………………….15
5.7 Switch case…………………………………………………………...17
6. Test Cases………………………………………………………………..19

1
1. Control Flow:
In computer science, control flow (or alternatively, flow of control) refers to the order in
which the individual statements, instructions or function calls of an imperative or a
declarative program are executed or evaluated. Within an imperative programming language,
a control flow statement is a statement whose execution results in a choice being made as to
which of two or more paths should be followed. For non-strict functional languages,
functions and language constructs exist to achieve the same result, but they are not
necessarily called control flow statements.
The kinds of control flow statements supported by different languages vary, but can be
categorized by their effect:
 continuation at a different statement (unconditional branch or jump),
 executing a set of statements only if some condition is met (choice - i.e., conditional
branch),
 executing a set of statements zero or more times, until some condition is met (i.e.,
loop - the same as conditional branch),
 executing a set of distant statements, after which the flow of control usually returns
(subroutines, coroutines, and continuations),
 Stopping the program, preventing any further execution (unconditional halt).
Interrupts and signals are low-level mechanisms that can alter the flow of control in a way
similar to a subroutine, but usually occur as a response to some external stimulus or event
(that can occur asynchronously), rather than execution of an 'in-line' control flow statement.
Self-modifying code can also be used to affect control flow through its side effects, but does
not usually involve an explicit control flow statement.
At the level of machine or assembly language, control flow instructions usually work by
altering the program counter. For some CPUs the only control flow instructions available are
conditional or unconditional branch instructions (also called jumps).
2. Control flow Graph:
In a control flow graph each node in the graph represents a basic block, i.e. a straight-line
piece of code without any jumps or jump targets; jump targets start a block, and jumps end a
block. Directed edges are used to represent jumps in the control flow. There are, in most
presentations, two specially designated blocks: the entry block, through which control enters
into the flow graph, and the exit block, through which all control flow leaves.
3. Control Flow Diagram:
A control flow diagram (CFD) is a diagram to describe the control flow of a business process,
process or program. A control flow diagram can consist of a subdivision to show sequential
steps, with if-then-else conditions, repetition, and/or case conditions. Suitably annotated
geometrical figures are used to represent operations, data, or equipment, and arrows are used
to indicate the sequential flow from one to another.

2
4. Browsing:
First of all we have to browse a file from the system by click on the browse that is displaying
on a main page. The main page has three sections
 Program: Which the user has to be browsed.
 Control flow graph: This is diagrammatic representation of the program with the
help of nodes and edges to calculate the cyclomatic complexity of program.
 Linear Independent Paths: These are different possible paths from starting of
control to the end of the program.
 Nodes: Displaying the total nodes of a browsed program.
There are two buttons are available on main page.
 Browse file: It is used to browse the file from system.
 Show Graph: It is used to display the control flow graph of browsed program.
Figure 1: Screenshot of main page
Step 1: Click on “browse file” then it displays a new window for browsing.

3
Figure 2: Screenshot of browsing a file
Step 2: Select an appropriate file.
Step 3: Click on “open” then program will be browsed and displayed on main page.
Figure 3: Screenshot of browsed program

Step 4: Click on “show graph” then control flow graph, node and linearly independent paths
will be displayed on main page.
4
Figure 4: Screenshot of displayed CFG
This program works for:
 For loop
 If statement
 If - else – for
 For - if
 Nested if
 If statement (with two conditions)
 Switch case

5
5. Test Cases:
5.1 Program: For Loop
main()
{
int i;
for(i=0;i<=3;i++)
{
print i;
}
}
Control Flow Graph 1:
Figure 5: CFG for For loop

6
Screenshot 1:
Figure 6: Screenshot of CFG for For loop

7
5.2 Program: If (Alterations)
main()
{
int a, b;
if(a<=b)
{
print a;
}
else
{
print b;
}
}
Figure 7: CFG for If

8
Screenshot 2:
Figure 8: Screenshot of CFG for If

9
5.3 Program: If - else - for
main()
{
if (a<=b)
Print a;
else
for(i=0;i<=3;i++)
{
print i;
}
}
Figure 9: CFG for If – else- for

10
Screenshot 3:
Figure 10: Screenshot of CFG for If – else- for

11
5.4 Program: Nested if
main()
{
int a, b;
if(a<=b)
{
if(a<=b)
{ print a;
}
else
{ print b;
}
}
else
{
print b;
}
}
Figure 11: CFG for Nested if

12
Screenshot 4:
Figure 12: Screenshot of CFG for Nested if

13
5.5 Program: If-for
main()
{
int a,b,i;
if (a<=b)
{
for(i=0;i<=3;i++)
{
print i;
}
}
}
Figure 13: CFG for if-for

14
Screenshot 5:
Figure 14: Screenshot of CFG for if-for

15
5.6 Program: If with two conditions
main()
{
int a, b;
if(a<b && a==b)
{
print a;
}
else
{
print b;
}
}
Figure 15: CFG for If with two conditions

16
Screenshot 6:
Figure 16: Screenshot of CFG for If with two conditions

17
5.7 Program: Switch Case
void main()
{
int i=10;
switch(i)
{
case 1:
print i++;
break;
case 2:
print i--;
break;
default:
print i;
}
}

18
Figure 17: CFG for switch
Screenshot 7:
Figure 18: Screenshot of CFG for switch

19
6. Test Cases
1. To generate the test cases by applying various testing methods to the switch case
program.
CASES (i): 1<= i<=5
1. View marks
2. Update marks
3. Add marks
4. Delete marks
5. Find marks
Marks (m): 0<=m<=100
Roll_No. (r): 1<=r<=30
A) Equivalence Class Testing Methods:
1. Weak Normal Equivalence Class Testing:
Test Case Options(i) Marks(m) Roll_No.(r)
T1 3 15 60
2. Strong Normal Equivalence Class Testing:
The test case of this class is same as weak normal equivalence class testing
because there are no any subintervals (No equivalence class).
3. Weak Robust Equivalence Class Testing:
Test Case Options(i) Roll_No.(r) Marks(m)
T2 0 15 60
T3 6 15 60
T4 3 0 60
T5 3 31 60
T6 3 15 -1
T7 3 15 101
4. Strong Robust Equivalence Class Testing:
T10 0 0 60
T11 6 31 60
T12 0 15 -1
T13 6 15 101
T14 3 0 -1
T15 3 31 101

20
T16 0 0 -1
T17 6 31 101
5. Robust Mixed Equivalence Class Testing: Combine invalid values with other
valid values.
Test Cases= Max (1, 1, 1) + 6 = 7
[-∞, 1) (5, ∞] =2
[-∞, 1) (30, ∞)= 2
[-∞, 0) (100, ∞]= 2
T1 3 15 60
T2 0 0 -1
T3 0 0 101
T4 0 31 -1
T5 0 31 101
T6 6 0 -1
T7 6 0 101
T8 6 31 -1
T9 6 31 101
B) Boundary Value Testing Methods:
6. Boundary Value Analysis:
T1 3 15 0
T2 3 15 1
T3 3 15 60
T4 3 15 99
T5 3 15 100
T6 3 1 60
T7 3 2 60
T8 3 29 60
T9 3 30 60
T10 1 15 60
T11 2 15 60
T12 4 15 60
T13 5 15 60

21
7. Robustness Testing:
It includes min-, min, min+, nom, max-, max, max+ for any one variable and for
other variables, it takes only nominal value. It adds four more test cases in
boundary value analysis.
T1 3 15 -1
T2 3 15 0
T3 3 15 1
T4 3 15 60
T5 3 15 99
T6 3 15 100
T7 3 15 101
T8 3 0 60
T9 3 1 60
T10 3 2 60
T11 3 29 60
T12 3 30 60
T13 3 31 60
T14 0 15 60
T15 1 15 60
T16 2 15 60
T17 4 15 60
T18 5 15 60
T19 6 15 60
8. Worst Case Testing: In this testing the cases are generated by making the valid
combinations ( min, min+, nom, max-, max,) of options, roll_no and marks,
basically it is a Cartesian product of i, m and r.
{imin}{rmin, rmin+, rnom, rmax-, rmax}{mmin, mmin+, mnom, mmax-,
mmax}=25
{imin+}{rmin, rmin+, rnom, rmax-, rmax}{mmin, mmin+, mnom, mmax-,
mmax}=25
{inom}{rmin, rmin+, rnom, rmax-, rmax}{mmin, mmin+, mnom, mmax-,
mmax}=25
{imax-}{rmin, rmin+, rnom, rmax-, rmax}{mmin, mmin+, mnom, mmax-,
mmax}=25
{imax}{rmin, rmin+, rnom, rmax-, rmax}{mmin, mmin+, mnom, mmax-,
mmax}=25
Total Test Cases= 25+25+25+25+25= 125
9. Robust Worst Case Testing: In this testing the cases are generated by making
the valid and invalid combinations (min-, min, min+, nom, max-, max,max+) of
options, roll_no and marks, basically it is a Cartesian product of i, m and r.

{imin-}{rmin-, rmin, rmin+, rnom, rmax-, rmax, rmax+}{mmin-, mmin, mmin+,
mnom, mmax-, mmax, mmax+}=49
{imin}{rmin-, rmin, rmin+, rnom, rmax-, rmax, rmax+}{mmin-, mmin, mmin+,
{imin+}{rmin-, rmin, rmin+, rnom, rmax-, rmax, rmax+}{mmin-, mmin, mmin+,
{inom}{rmin-, rmin, rmin+, rnom, rmax-, rmax, rmax+}{mmin-, mmin, mmin+,
{imax-}{rmin-, rmin, rmin+, rnom, rmax-, rmax, rmax+}{mmin-, mmin, mmin+,
{imax}{rmin-, rmin, rmin+, rnom, rmax-, rmax, rmax+}{mmin-, mmin, mmin+,
{imax+}{rmin-, rmin, rmin+, rnom, rmax-, rmax, rmax+}{mmin-, mmin, mmin+,
Total Test Cases= 49*7= 343
22
10. Weak Diagonal In Boundary Value Testing:
T1 1 1 0
T2 2 2 1
T3 3 15 60
T4 4 29 99
T5 5 30 100
11. Weak In Boundary Value Testing: (min, min+, nom, max-,max)
T1 3 15 0
T2 3 15 1
T3 3 15 60
T4 3 15 99
T5 3 15 100
T6 3 1 60
T7 3 2 60
T8 3 29 60
T9 3 30 60
T10 1 15 60
T11 2 15 60
T12 4 15 60
T13 5 15 60
12. Weak Out Boundary Value Testing: (min-, min+, nom, max-,max+)

23
T1 3 15 -1
T2 3 15 1
T3 3 15 60
T4 3 15 99
T5 3 15 101
T6 3 0 60
T7 3 2 60
T8 3 29 60
T9 3 31 60
T10 0 15 60
T11 2 15 60
T12 4 15 60
T13 6 15 60
13. Weak Simple Out Boundary Value Testing: (min-, min+, max-,max+)
T1 3 15 -1
T2 3 15 1
T3 3 15 99
T4 3 15 101
T5 3 0 60
T6 3 2 60
T7 3 29 60
T8 3 31 60
T9 0 15 60
T10 2 15 60
T11 4 15 60
T12 6 15 60
14. Weak Simple Out Boundary Value Testing:
T1 1 1 0
T2 1 1 100
T3 1 30 0
T4 1 30 100
T5 5 1 0
T6 5 1 100
T7 5 30 0
T8 5 30 100
T9 2 2 1
T10 2 2 99
T11 2 29 10
T12 2 29 99
T13 4 2 1
T14 4 2 99
T15 4 29 1

24
T16 4 29 99
T17 3 15 60
2. To generate the test cases by applying various testing methods to the insertion
sort program.
The Maximum number (M) user can enter = 50
The Range (R) of number that is entered by user = 1 to 1000
1<=M<=50 and 1<=R<=1000
A) Equivalence Class Testing Methods:
1. Weak Normal Equivalence Class Testing:
Test case Maximum number (M) Range (R)
T1 30 550
2. Strong Normal Equivalence Class Testing:
The test case of this class is same as weak normal equivalence class testing
because there are no any subintervals (No equivalence class).
3. Weak Robust Equivalence Class Testing:
T2 0 550
T3 51 550
T4 25 0
T5 25 1001
4. Strong Robust Equivalence Class Testing:
T6 0 0
T7 51 1001
5. Robust Mixed Equivalence Class Testing:
Max (1, 1) + 4= 5
[-∞, 1) (50, ∞] = 2 and [-∞, 1) (1000, ∞] = 2
T1 25 550
T2 0 0

25
T3 0 1001
T4 51 0
T5 51 1001
B) Boundary Value Testing Methods:
6. Boundary Value Analysis:
Test Case Maximum number (M) Range (R)
T1 1 550
T2 2 550
T3 30 550
T4 49 550
T5 50 550
T6 30 1
T7 30 2
T8 30 999
T9 30 1000
7. Robustness Testing:
It includes min-, min, min+, nom, max-, max, max+ for any one variable and for
other variables, it takes only nominal value. It adds four more test cases in
boundary value analysis.
T1 0 550
T2 1 550
T3 2 550
T4 30 550
T5 49 550
T6 50 550
T7 51 550
T8 30 0
T9 30 1
T10 30 2
T11 30 999
T12 30 1000
T13 30 1001
8. Worst Case Testing: In this testing the cases are generated by making the valid
combinations ( min, min+, nom, max-, max,) of Maximum number (M) and
Range (R), basically it is a Cartesian product of M and R.

26
{Mmin}{Rmin, Rmin+, Rnom, Rmax-, Rmax}= 5
{Mmin+}{Rmin, Rmin+, Rnom, Rmax-, Rmax}= 5
{Mnom}{Rmin, Rmin+, Rnom, Rmax-, Rmax}= 5
{Mmax-}{Rmin, Rmin+, Rnom, Rmax-, Rmax}= 5
{Mmax}{Rmin, Rmin+, Rnom, Rmax-, Rmax}= 5
Total Test Cases= 5+5+5+5+5= 25
9. Robust Worst Case Testing: In this testing the cases are generated by making
the valid and invalid combinations (min-, min, min+, nom, max-, max, max+) of
Maximum number (M) and Range (R), basically it is a Cartesian product of of M
and R.
{Mmin-}{ Rmin-, Rmin, Rmin+, Rnom, Rmax-, Rmax, Rmax+}= 7
{Mmin}{ Rmin-, Rmin, Rmin+, Rnom, Rmax-, Rmax, Rmax+}= 7
{Mmin+}{ Rmin-, Rmin, Rmin+, Rnom, Rmax-, Rmax, Rmax+}= 7
{Mnom}{ Rmin-, Rmin, Rmin+, Rnom, Rmax-, Rmax, Rmax+}= 7
{Mmax-}{ Rmin-, Rmin, Rmin+, Rnom, Rmax-, Rmax, Rmax+}= 7
{Mmax}{ Rmin-, Rmin, Rmin+, Rnom, Rmax-, Rmax, Rmax+}= 7
{Mmax+}{ Rmin-, Rmin, Rmin+, Rnom, Rmax-, Rmax, Rmax+}= 7
Total Test Cases= 7*7= 49
10. Weak Diagonal In Boundary Value Testing:
T1 1 1
T2 2 2
T3 30 550
T4 49 999
T5 50 1000
11. Weak In Boundary Value Testing: (min, min+, nom, max-,max)
T1 30 1
T2 30 2
T3 30 550
T4 30 999
T5 30 1000
T6 1 550
T7 2 550
T8 49 550
T9 50 550

27
12. Weak Out Boundary Value Testing:
T1 30 0
T2 30 1
T3 30 550
T4 30 1000
T5 30 1001
T6 0 550
T7 1 550
T8 50 550
T9 51 550
13. Weak Out Boundary Value Testing: (No nominal case)
T1 30 0
T2 30 1
T3 30 1000
T4 30 1001
T5 0 550
T6 1 550
T7 50 550
T8 51 550
14. Robust Weak Boundary Value Testing:
T1 0 550
T2 1 550
T3 2 550
T4 30 550
T5 49 550
T6 50 550
T7 51 550
T8 30 0
T9 30 1
T10 30 2
T11 30 999
T12 30 1000
T13 30 1001
15. Robust Weak Simple Boundary Value Testing:

28
T1 0 550
T2 1 550
T3 2 550
T4 49 550
T5 50 550
T6 51 550
T7 30 0
T8 30 1
T9 30 2
T10 30 999
T11 30 1000
T12 30 1001
16. Weak Corner In Boundary Value Testing:
T1 1 1
T2 2 2
T3 49 2
T4 50 1
T5 30 550
T6 1 1000
T7 2 999
T8 49 999
T9 50 1000
17. Robust Corner Out Boundary Value Testing:
T1 1 1
T2 50 1
T3 1 1000
T4 50 1000
T5 0 1
T6 1 0
T7 51 1
T8 50 0
T9 0 1000
T10 1 1001
T11 50 1001
T12 51 1000

29
3. Decision Table Based Testing:
In a university, teacher assign grade on the basis of percentage and an attendance. If
absents are more than five then then original grades (based on only percentage) will
be shifted by one (ex: A to B). If any student have already F grade then it remains
same. Grades are basis on following criteria:
Percentage (P)
Grade (G)
P>=90 A
80<= P<90 B
70<= P<80 C
60<= P<70 D
33<= P<60 E
P<33 F
Conditions:
C1: Absent <=5
C2: P>=90
C3: 80<= P<90
C4: 70<= P<80
C5: 60<= P<70
C6: 33<= P<60
C7: P<33
R: Rules

Rules R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12
30
Conditions:
C1 Y Y Y Y Y Y N N N N N N
C2 Y Y
C3 Y Y
C4 Y Y
C5 Y Y
C6 Y Y
C7 Y Y
Actions:
A √
B √ √
C √ √
D √ √
E √ √
F √ √ √

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