1. Chapter 13 & 14 Software Testing Strategies and Techniques
Software Engineering: A Practitioner’s Approach, 6th edition
by Roger S. Pressman Ir. I. Joko Dewanto., MM
Universitgas Esa Unggul

2. Software Testing Testing is the process of exercising a
program with the specific intent of finding
errors prior to delivery to the end user.

3. What Testing Shows errors requirements conformance performance
an indication
of quality

4. Who Tests the Software? developer independent tester
Understands the system
Must learn about the system,
but, will test "gently"
but, will attempt to break it
and, is driven by "delivery"
and, is driven by quality

5. Validation vs Verification
Verification – Are we building the product right?
Is the code correct with respect to its specification?
Validation – Are we building the right product?
Does the specification reflect what it should?

6. Testing Strategy unit test integration test system validation test

7. Testing Strategy
Begin with unit testing and work your way up to system testing.
Unit testing – test individual components (modules in procedural languages; classes in OO languages)
Integration testing – test collections of components that must work together
Validation testing – test the application as a whole against user requirements
System testing – test the application in the context of an entire system

8. Unit Testing
module
to be
tested
results
software
engineer
test cases

9. Unit Testing module to be tested interface local data structures
boundary conditions
independent paths
error handling paths
test cases

10. Unit Test Environment test cases RESULTS driver Module stub stub
interface
local data structures
Module
boundary conditions
independent paths
error handling paths
stub
stub
test cases
RESULTS

11. Integration Testing Strategies
Options:
• the “big bang” approach
• an incremental construction strategy

12. Top Down Integration A top module is tested with stubs B F G
stubs are replaced one at
a time, "depth first" C
as new modules are integrated,
some subset of tests is re-run D E

13. Bottom-Up IntegrationF G
drivers are replaced one at a
time, "depth first" C
worker modules are grouped into
builds and integrated D E
cluster

14. Regression Testing
The selective retesting of a modified system to help ensure that no bugs have been introduced during modification.
Fixing one part of the code can break another

15. High Order Testing Validation testing System testing
Focus is on software requirements
System testing
Focus is on system integration
Alpha/Beta testing
Focus is on customer usage
Recovery testing
forces the software to fail in a variety of ways and verifies that recovery is properly performed
Security testing
verifies that protection mechanisms built into a system will, in fact, protect it from improper penetration
Stress testing
executes a system in a manner that demands resources in abnormal quantity, frequency, or volume
Performance Testing
test the run-time performance of software within the context of an integrated system

16. What is a “Good” Test?
A good test is one that has a high probability of finding an error.

17. Test Case Design "Bugs lurk in corners and congregate at
boundaries ..."
Boris Beizer
OBJECTIVE
to uncover errors
CRITERIA
in a complete manner
CONSTRAINT
with a minimum of effort and time

18. Exhaustive Testing There are 10 possible paths! If we execute one
loop < 20 X 14
There are 10 possible paths! If we execute one
test per millisecond, it would take 3,170 years to
test this program!!

19. Selective Testing
Selected path
loop < 20 X

20. Software Testing white-box black-box methods methods Methods
Strategies

21. White-Box Testing ... our goal is to ensure that all
statements and conditions have
been executed at least once ...

22. Why Cover? logic errors and incorrect assumptions
are inversely proportional to a path's
execution probability
we often
believe
that a path is not
likely to be executed; in fact, reality is
often counter intuitive
typographical errors are random; it's
likely that untested paths will contain
some

23. Basis Path Testing First, we compute the cyclomatic complexity:
number of simple decisions + 1 or
number of enclosed areas + 1
In this case, V(G) = 4

24. Cyclomatic Complexity
A number of industry studies have indicated
that the higher V(G), the higher the probability
or errors.
modules
V(G)
modules in this range are
more error prone

25. Basis Path Testing Next, we derive the independent paths:1 2 3 4 5 6 7 8
independent paths:
Since V(G) = 4,
there are four paths
Path 1: 1,2,3,6,7,8
Path 2: 1,2,3,5,7,8
Path 3: 1,2,4,7,8
Path 4: 1,2,4,7,2,4,...7,8
Finally, we derive test
cases to exercise these
paths.

26. Basis Path Testing Notes
you don't need a flow chart,
but the picture will help when
you trace program paths
count each simple logical test,
compound tests count as 2 or
more
basis path testing should be
applied to critical modules

27. Black-Box Testing
requirements
output
input
events

28. Equivalence Partitioning
user
queries
output
formats FK
input
mouse
picks
data
prompts

29. Sample Equivalence Classes
Valid data
user supplied commands
responses to system prompts
file names
computational data
physical parameters
bounding values
initiation values
output data formatting
responses to error messages
graphical data (e.g., mouse picks)
Invalid data
data outside bounds of the program
physically impossible data
proper value supplied in wrong place

30. Boundary Value Analysis
user
queries
output
formats FK
input
mouse
picks
data
prompts
output
domain
input domain

31. OOT Methods: Behavior Testing
The tests to be designed should achieve all state coverage [KIR94]. That is, the operation sequences should cause the Account class to make transition through all allowable states