White-Box Testing
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White-Box Testing Pfleeger, S. Software Engineering Theory and Practice 2 nd Edition. Prentice Hall, 2001. Ghezzi, C. et al., Fundamentals of Software Engineering. Prentice Hall, 2002. Pressman, R., Software Engineering A Practitioner’s Approach, Mc Graw Hill, 2005. 1209
description
White-Box Testing. Pfleeger, S. Software Engineering Theory and Practice 2 nd Edition. Prentice Hall, 2001. Ghezzi, C. et al., Fundamentals of Software Engineering. Prentice Hall, 2002. Pressman, R., Software Engineering A Practitioner’s Approach, Mc Graw Hill, 2005. 1209. - PowerPoint PPT Presentation
Transcript of White-Box Testing
White-Box Testing
Pfleeger, S. Software Engineering Theory and Practice 2nd Edition. Prentice Hall, 2001.Ghezzi, C. et al., Fundamentals of Software Engineering. Prentice Hall, 2002.Pressman, R., Software Engineering A Practitioner’s Approach, Mc Graw Hill, 2005.
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White Box Testing• Also known as:
– Glass box testing– Structural testing
• Test set is derived from structure of code • Code structure represented as a Control Flow Graph• Goal is to cover the CFG
Control Flow Graphs• Programs are made of three kinds of statements:
Control Flow Graph (CFG)
Sequence If-then-else If-then Iterative
Example 1: CFG
1. read (result);2. read (x,k)3. while result < 0 then {4. ptr false5. if x > k then6. ptr true7. x x + 18. result result + 1 }9. print result
Write a CFGExample 2
1. if (a < b) then 2. while (a < n)3. a a + 1;4. else 5. while (b < n)6. b b + 1;
Answers Example 3
1. read (a,b); 2. if (a 0 && b 0) then {3. c a + b;4. if c > 10 then 5. c max6. else c min }7. else print ‘Done’
AnswersExample 4
1. read (a,b); 2. if (a 0 || b 0) then {3. c a + b4. while( c < 100)5. c a + b; }6. c a * b
Cyclomatic Complexity• Software metric for the logical complexity of a program.• Defines the number of independent paths in the basis set of a
program
• Provides the upper bound for the number of tests that must be conducted to ensure that all statements been have executed at least once
• For Edges (E) and Nodes (N) V(G) = E – N + 2
Complexity of CFGs
1
2
3
1 3,4
5 6
Join
3,4
5
Join
Example1
2,3
6
10
8
4,5
9
7
11
Example 1: CFG
3
4,5
6
Join
9
7,8
1,2
Example 21
2
3
Join
5
6
Answers1,2
Join
3,4
5 6
Join
7
Answers
1, 2
3
Join
4
5
6
Criteria
• Statement coverage• Branch coverage• Condition coverage
• (lots of others …)
Branch Coverage• Each edge of a program’s CFG is
traversed at least once in some test.
• Independent paths: – 1, 2, 3, 9– 1, 2, 3, 4, 5, 6, 7, 8, 3, …, 9– 1, 2, 3, 4, 5, 7, 8, 3, …, 9
Example 1
3
4,5
6
Join
9
7,8
1,2
Criteria• Statement coverage• Branch coverage• Condition coverage
– Every complex condition is made true and false by every possible combination
– E.G., (x and y)• x = true, y = true• x=false, y=true• x = true, y= false• x =false, y = false
AND Condition
1, 2A
2B
Join
3
4
OR Condition
1,2A
3
Join
4
2B
5
Path Coverage-1• Every distinct path through code is
executed at least once• Basis set does not yield minimal test set• Example
1. read (x)2. read (z)3. if x 0 then begin4. y x * z;5. x z end6. else print ‘Invalid’ 7. if y > 1 then8. print y9. else print ‘Invalid’
• Test Paths:1, 2, 3, 4, 5, J1, 7, 8, J21, 2, 3, 4, 5, J1, 7, 9, J21, 2, 3, 6, J1, 7, 8, J2,1, 2, 3, 6, J1, 7, 9, J2
1,2,3
4,5
Join1
6
7
8
Join2
9
Def-Use Coverage• Def-use coverage: every path
from every definition of every variable to every use of that definition is exercised in some test.
• Example1. read (x)2. read (z)3. if x 0 then begin4. y x * z;5. x z end6. else print ‘Invalid’ 7. if y > 1 then8. print y9. else print ‘Invalid’
1,2,3
4,5
Join
6
7
8
Join
9
Def: x, zUse: x
Def: y, xUse: x, z
Use: none
Use: y
Use: y Use: none
Test Path: 1, 2, 3, 4, 5, 7, 8, J
Strength of Coverage
What paths don’t tell you
• Timing errors• Unanticipated error conditions• User interface inconsistency (or anything
else)• Configuration errors• Capacity errors
