1. Theory and Practice of Software Testing
Chapter 14 Presman
Software Testing Tactics

2. Testing objectives [MYE79]
Testing is a process of executing a program with the goal of finding an error.
A good test is one that has a high probability of finding an error

3. Good Testing Has a high probability of finding an error
Is Not redudant
Should be “best f breed”
Should be neither too simple nor too complex

4. Testing Techniques Test information flow Test case design
White box testing
Basis path testing
Black box Testing
Equivalence Partitioning
Boundary Value Analysis

5. Test Information flow testing Software configuration evaluation errors
results
Error rate data
debug
corrections
testing
Reliability
model
test
configuration
Predicted
reliability
Expected results

6. White-Box testing Sometime called Glass-box testing
A test case design philosophy that uses the control program structure to derive test case
Knowledge of the program is used to identify additional test cases

7. White-Box testing
Objective is to exercise all program statements (not all path combinations)
Every instruction
Every decision
A set of paths that meets these criteria is said to provide cover or complete cover

8. White-box testing

9. Basis Path Testing One of white box testing technique
The objective of basis path testing is to derive a logical complexity measure of procedural design and defining a basis set of execution paths
Test case derived to exercise the basis set to execute every statement in the program at least one time during testing

10. Basis Path testing
Uses flow graph or program graph that shows nodes representing program decisions and vertex representing the flow of control
Statements with conditions are therefore nodes in the flow graph
Node is any point in the program where the control either joins, or forks or both
Nodes are joined by edges or links

12. Contoh Program

14. Predicate Node Node that contain a conditiona
Can be compound with logical operator : “and” / “or”

18. Independent Path (IP)
Independent Path is any path through the program that introduces at least one new set processing statement or a new condition

19. A set of independent path … … …

20. Process to deriving Test Cases
Map the design or code to the corresponding flow graph
Compute the cyclomatic complexity of the resultant flow graph
Identify a basis set of independent paths
Prepare test cases that will force execution of each path in the basis set

21. Cyclomatic Complexity : V(G)
Metric that provides a quantitative measure of logical complexity of a program
Define the number of independent path in the basis set of a program
The number of tests cases used to test all control statements equals the cyclomatic complexity

22. Compute Cyclomatic Complexity
V(G) = R
V(G)= P +1
V(G) = E –N +2
Where :
R is the number of regions of the flow graph
P is the number of logical expressions (or predicates node)
E is the number of flow graph edges
N is the number of flow graph nodes

23. Path 1 test case Specification of Inputs
Value (k) = valid input, where k < i
Value (i) = -999 where 2 i 100
Specification of Output (expected results):
correct average based on k values and correct totals should be computed
Note:
This test case must be test as part of path 4, 5, and 6 tests

24. Path 2 test case Inputs Expected results: Value (1) = -999
Average = -999; other total at initial values

25. Path 3 test case Inputs Expected results:
Attempt to process 101 or more values
The first 100 values should be valid
Expected results:
correct average based on k values and correct totals should be computed

26. Path 4 test case Inputs Expected results:
Value (i) = valid input, i < 100
Value (k) < minimum where k<i
Expected results:
correct average based on k values and correct totals should be computed

27. Path 5 test case Inputs Expected results:
Value (i) = valid input where i< 100
Value (i)> maximum where k i
Expected results:
correct average based on n values and correct totals should be computed

28. Path 6 test case Inputs Expected results:
Value (i) = valid input where i< 100
Expected results:
correct average based on n values and correct totals should be computed

29. Main tactics on path selection
A sufficient number of paths to achieve coverage
Selection of short, functionally sensible paths
Minimizing the number of changes from path to path (one decision changing at a time)
Favor more but simpler paths over fewer but complicated paths

30. Effectiveness path testing
Approximately between 60-70% of all bugs can be caught in unit testing using basis path testing

31. Main Limitations of Basis path testing
Can not be used to show totally wrong or missing functions
Interface errors may not be caught
Database errors may not be caught
Not all initialization errors are caught by path testing

32. Graph Metrices
A tabular representation of flow graph with link weight addition to provide information about control flow
A square matrix whose size ( row & column) is equal to the number of node on flow graph
Existing connection ( 1 & 0)

33. Link Weight Probability an edge will be executed
Processing time expended,
Memory required,
Resources required,
during traversal of a link

34. Control Structure Testing
Condition Testing
a test case design method that exercise the logical conditions contained in a program module
Data Flow Testing
a method to select a test path of a program according to the location of definitions and uses of variable in the program
Loop Testing
a white box testing technique that focuses exclusively on the validity of loop construct

35. Loop Testing 4 different classes of loop : Simple loop Nested loop
Concatenated loop
Unstructured loop

37. Simple Loop test criteria
The following set of test can be applied to a simple loop
of size max
Skip the loop entirely
One pass through the loop
Two passes through the loop before existing
M passes through the loop where M < max
max-1, max, max+1 passes through the loop

38. Nested Loop test criteria
Start at the inner loop. Set all other loop to a minimum value
Conduct simple loop testing for the innermost loop
Work outward, repeat for all loops. Keeping all other outer loops at minimum value & other nested loops to “typical value”
Continue until all loops tested

39. Concatenated Loops If independent loops, use simple loop testing
If dependent, treat as nested loops

40. Unstructured Loops
Don’t test - redesign