1. Chapter 11, Testing

2. Tell me how are you going to test the CALCULATOR

3. To Summarize the calculator example
Valid Input
Invalid Input
Character: A, B, C,
Abnormal sequence
Boundary test
Large number
Negative number
zero
Check internal implementation boundaries
size of stack
Non-functional test
Performance test
Appearance
Usability
Documentation
Timing

4. How to design test cases?
Test the functional requirement
Use case testing
Black box testing
Equivalence partition testing
Boundary testing ….
Test the non-functional requirement
Performance testing
Acceptance testing
Installation testing

5. Black box testing
Also known as functional testing. A software testing technique whereby the internal workings of the item being tested are not known by the tester.
For example, in a black box test on a software design the tester only knows the inputs and what the expected outcomes should be and not how the program arrives at those outputs.
The tester does not ever examine the programming code and does not need any further knowledge of the program other than its specifications.

6. Black box testing The advantages of this type of testing include:
The test is unbiased because the designer and the tester are independent of each other.
The tester does not need knowledge of any specific programming languages.
The test is done from the point of view of the user, not the designer.
Test cases can be designed as soon as the specifications are complete.
The disadvantages of this type of testing include:
The test can be redundant if the software designer has already run a test case.
The test cases are difficult to design.
Testing every possible input stream is unrealistic because it would take a inordinate amount of time; therefore, many program paths will go untested.

7. White box testing
Also known as glass box, structural, clear box and open box testing. A software testing technique whereby explicit knowledge of the internal workings of the item being tested are used to select the test data.
Unlike black box testing, white box testing uses specific knowledge of programming code to examine outputs. The test is accurate only if the tester knows what the program is supposed to do. He or she can then see if the program diverges from its intended goal.
White box testing does not account for errors caused by omission, and all visible code must also be readable.

8. Black box testing and white box testing compared
White box testing is concerned only with testing the software product, it cannot guarantee that the complete specification has been implemented.
Black box testing is concerned only with testing the specification, it cannot guarantee that all parts of the implementation have been tested.
Thus black box testing is testing against the specification and will discover faults of omission, indicating that part of the specification has not been fulfilled.
White box testing is testing against the implementation and will discover faults of commission, indicating that part of the implementation is faulty.
In order to fully test a software product both black and white box testing are required.

9. Black box testing and white box testing compared
White box testing is much more expensive than black box testing. It requires the source code to be produced before the tests can be planned and is much more laborious in the determination of suitable input data and the determination if the software is or is not correct.
The advice given is to start test planning with a black box test approach as soon as the specification is available.
White box planning should commence as soon as all black box tests have been successfully passed, with the production of flowgraphs and determination of paths. The paths should then be checked against the black box test plan and any additional required test runs determined and applied.

10. Quality assurance vs. quality control
The consequences of test failure at this stage may be very expensive.
A failure of a white box test may result in a change which requires all black box testing to be repeated and the re-determination of the white box paths.
The cheaper option is to regard the process of testing as one of quality assurance rather than quality control. The intention is that sufficient quality will be put into all previous design and production stages so that it can be expected that testing will confirm that there are very few faults present, quality assurance, rather than testing being relied upon to discover any faults in the software, quality control.

11. A test case has five attributes.
Test Cases
A test case is a set of input data and expected results that exercises a component with the purpose of causing failures and detecting faults.
A test case has five attributes.
Attributes
Description
Name
Name of test case
Location
Full path name of executable
Input
Input data or commands
Oracle
Expected results
Log
Output produced by the test

12. Testing: from the development process point of view
Requirement
Design
Implementation &
Testing
Final System
Test case development &
Testing
Requirement
Final System
Design&
Implementation

13. Review of last class Case Study Example: the calculator
Testing Computer Software, Cem Kaner, Jack Falk, Hung Quoc Nguyen

14. The objectives and limits of Testing
You can’t test a program completely
You can’t test the program’s response to every possible Input
You’d have to test all valid inputs
You’d have to test all invalid inputs, e.g., everything that you can enter at the keyboard
You’d have to test all edited inputs – the <Backspace> example
You’d have to test all variations on input timing
You can’t test every path the program can take
Myers’ simple program in 1979 – 20 lines of code, 100 trillion paths; a faster tester could test them in a billion years.
Specifications often contain errors.
You can’t prove programs correct using logic – how do you prove the proof procedure is correct.

15. The objectives and limits of Testing
The program doesn’t work correctly
Beizer’s review estimates the average number of errors in programs released to Testing at 1 to 3 bugs per 100 executable statements -- These are public bugs
Private bugs – before releasing to the tester – 1.5 errors per executable statement. Most programmers catch and fix more than 99% of their mistakes before releasing a program for testing.
Is testing a failure if the program doesn’t work correctly
We have seen project managers blame testers for continuing to find errors in a program that’s behind schedule.
Testers shouldn’t want to verify that a program runs correctly
If you think your task is to find problems, you will look harder for them than if you think your task is to verify that the program has none (Myers, 1979)

16. So, Why Test?
The purpose of testing a program is to find problems in it

17. Outline Terminology Types of errors Dealing with errors
Component Testing
Unit testing
Integration testing
Testing Strategy
System testing
Function testing
Structure Testing
Performance testing
Acceptance testing
Installation testing

18. What is this?
A failure?
An error?
A fault?
Need to specify the desired behavior first!

19. Fault (Bug): The mechanical or algorithmic cause of an error.
Terminology
Failure: Any deviation of the observed behavior from the specified behavior.
Error: The system is in a state such that further processing by the system will lead to a failure.
Fault (Bug): The mechanical or algorithmic cause of an error.
Reliability: The measure of success with which the observed behavior of a system confirms to some specification of its behavior.
Software reliability is the probability that a software system will not cause system failure for a specified time under specified conditions.
There are many different types of errors and different ways how we can deal with them.

20. How do we deal with Errors and Faults?

21. Verification?

22. Modular Redundancy?

23. Declaring the Bug as a Feature?

24. Patching?

25. Testing?

26. Examples of Faults and Errors
Faults in the Interface specification
Mismatch between what the client needs and what the server offers
Mismatch between requirements and implementation
Algorithmic Faults
Missing initialization
Branching errors (too soon, too late)
Missing test for nil
Mechanical Faults (very hard to find)
Documentation does not match actual conditions or operating procedures
Errors
Stress or overload errors
Capacity or boundary errors
Timing errors
Throughput or performance errors

27. Dealing with Errors Verification: Modular redundancy:
The assumptions made in verification might be wrong
Proof might be buggy (omits important constraints; simply wrong)
Nevertheless, sometimes verification is required
How do you test a surgery robot
Modular redundancy:
Expensive
Declaring a bug to be a “feature”
Bad practice
Patching
Slows down performance
Testing (this lecture)
Testing is never good enough

28. Another View on How to Deal with Errors
Error prevention (before the system is released):
Use good programming methodology to reduce complexity
Use version control to prevent inconsistent system
Apply verification to prevent algorithmic bugs
Error detection (while system is running):
Testing: Create failures in a planned way
Debugging: Start with an unplanned failures
Monitoring: Deliver information about state. Find performance bugs
Error recovery (recover from failure once the system is released):
Data base systems (atomic transactions)
Modular redundancy
Recovery blocks

29. Some Observations
It is impossible to completely test any nontrivial module or any system
Theoretical limitations: Halting problem
Practial limitations: Prohibitive in time and cost
Testing can only show the presence of bugs, not their absence (Dijkstra)

30. Testing takes creativity
Testing often viewed as dirty work.
To develop an effective test, one must have:
Detailed understanding of the system
Knowledge of the testing techniques
Skill to apply these techniques in an effective and efficient manner
Testing is done best by independent testers
We often develop a certain mental attitude that the program should in a certain way when in fact it does not.
Programmer often stick to the data set that makes the program work
"Don’t mess up my code!"
A program often does not work when tried by somebody else.
Don't let this be the end-user.

31. Quiz #2

32. Black-box Testing
Focus: I/O behavior. If for any given input, we can predict the output, then the module passes the test.
Almost always impossible to generate all possible inputs ("test cases")
Goal: Reduce number of test cases by equivalence partitioning:
Divide input conditions into equivalence classes
Choose test cases for each equivalence class. (Example: If an object is supposed to accept a negative number, testing one negative number is enough)

33. Black-box Testing (Continued)
Selection of equivalence classes (No rules, only guidelines):
Input is valid across range of values. Select test cases from 3 equivalence classes:
Below the range
Within the range
Above the range
Input is valid if it is from a discrete set. Select test cases from 2 equivalence classes:
Valid discrete value
Invalid discrete value

34. Are These Enough? What is the best way to test these kinds of faults?
Two Interesting Test Cases
Create a folder named as “CON” (doesn’t matter if capital letter or small letter)
Open Microsoft Word and type =rand(200,99)
What is the best way to test these kinds of faults?
Another solution to select only a limited amount of test cases:
Get knowledge about the inner workings of the unit being tested => white-box testing

35. Boundary Testing A special case of equivalence testing
Focuses on the condition at the boundary of the equivalence classes.
The assumption behind boundary testing is that developers often overlook special cases at the boundary of the equivalence classes (e.g., 0, empty strings, year 2000).

36. Types of white-box testing
Focus: Thoroughness (Coverage). Every statement in the component is executed at least once.
Types of white-box testing
Path Testing
Loop Testing
State-Based testing

37. White-box Testing (Continued)
Path testing:
Make sure all paths in the program are executed
Loop Testing:
Cause execution of the loop to be skipped completely. (Exception: Repeat loops)
Loop to be executed exactly once
Loop to be executed more than once

38. Path testing
The assumption behind path testing is that, by exercising all possible paths through the code at least once, most faults will trigger failures.
The starting point for path testing is the flow graph.

40. Calculating the minimal number of test cases
Number of independent paths through the flow graph.
This is defined as the cyclomatic complexity CC
CC = number of edges – number of nodes +2
A path is linearly independent from others means the path can not be expressed by linear combinations of others.

41. Path testing (continue)
An example on book P. 456, 457,458
Using graph theory, it can be shown that the number of independent paths through the flow graph.
CC = number of edges – number of nodes +2

42. For the example on book Number of Test cases = 18 – 14 +2 = 6
Year = 0, month =1
Throw1
Year = 1901, month =1
N = 32, return
Year = 1901, month =2
N=28, return
Year = 1904, month =2
N=29, return
Year = 1901, month =4
N=30 return
Year = 1901, month =0
Throw 2

43. Loop Testing
A white box testing technique that exercises program loops
Loops are a highly fault-prone portion of source code.
Concatenated loops
Nested loops
Horrible loops

44. Loop Testing Example FindMean(float Mean, FILE ScoreFile)
{ SumOfScores = 0.0; NumberOfScores = 0; Mean = 0;
Read(Scor
eFile, Score);
/*Read in and sum the scores*/
while (! EOF(ScoreFile) {
if ( Score > 0.0 ) {
SumOfScores = SumOfScores + Score;
NumberOfScores++; }
Read(ScoreFile, Score); }
/* Compute the mean and print the result */
if (NumberOfScores > 0 ) {
Mean = SumOfScores/NumberOfScores;
printf("The mean score is %f \n", Mean);
} else
printf("No scores found in file\n"); }

45. White-box Testing Example: Determining the Paths
FindMean (FILE ScoreFile)
{ float SumOfScores = 0.0;
int NumberOfScores = 0;
float Mean=0.0; float Score;
Read(ScoreFile, Score);
while (! EOF(ScoreFile) {
if (Score > 0.0 ) {
SumOfScores = SumOfScores + Score;
NumberOfScores++; }
/* Compute the mean and print the result */
if (NumberOfScores > 0) {
Mean = SumOfScores / NumberOfScores;
printf(“ The mean score is %f\n”, Mean);
} else
printf (“No scores found in file\n”); 1 2 3 4 5 6 7 8 9

46. Constructing the Logic Flow Diagram

47. Finding the Test Cases Start 1 a (Covered by any data) 2 b
(Data set must contain at least
one value) 3
(Positive score) d e
(Negative score) c 4 5
(Data set must h
(Reached if either f or
be empty) f g 6
e is reached) 7 i j
(Total score > 0.0)
(Total score < 0.0) 8 9 k l
Exit

48. Test Cases Test case 1 : ? (To execute loop exactly once)
Test case 2 : ? (To skip loop body)
Test case 3: ?,? (to execute loop more than once)
These 3 test cases cover all control flow paths
Loop testing and path testing can work together
For the previous example:
path testing: = 4

49. Calculating the minimal number of test cases
Number of independent paths through the flow graph.
This is defined as the cyclomatic complexity CC
CC = number of edges – number of nodes +2
A path is linearly independent from others means the path can not be expressed by linear combinations of others.

50. Constructing the Logic Flow Diagram
Test cases: = 3
P1: 0, 1, 2, 3, 4, 6, 7, 8, 10
P2: 0, 1, 2, 3, 5, 6, 7, 8, 10
P3: 0, 1, 2, 3, 4, 6, 7, 9, 10
P4: 0, 1, 2, 3, 5, 6, 7, 9, 10
P4 = P3 + P2 –P1 10

51. Constructing the Logic Flow Diagram
Test cases: = 4
P1: 0, 1, 2, 3, 4, 6, 2, 7, 8, 10
P2: 0, 1, 2, 3, 5, 6, 2, 7, 8, 10
P3: 0, 1, 2, 7, 8, 10
P4: 0, 1, 2, 7, 9, 10
P5: 0, 1, 2, 3, 5, 6, 2, 7, 9, 10
P4 = P2 + P4 –P3

52. Test Cases testMethod( int y, int v){ int i=0; int x =y;
start
i=0; x=y
testMethod( int y, int v){
int i=0;
int x =y;
for (i=0; i< v ; i++){
if (x>0){
do A; }
else {
do B;
System.out.println(“finish method”);
for loop 5
x>0? A B
print
end

53. Comparison of White & Black-box Testing
White-box Testing:
Potentially infinite number of paths have to be tested
White-box testing often tests what is done, instead of what should be done
Cannot detect missing use cases
Black-box Testing:
Potential combinatorical explosion of test cases (valid & invalid data)
Often not clear whether the selected test cases uncover a particular error
Does not discover extraneous use cases ("features")
Both types of testing are needed
White-box testing and black box testing are the extreme ends of a testing continuum.
Any choice of test case lies in between and depends on the following:
Number of possible logical paths
Nature of input data
Amount of computation
Complexity of algorithms and data structures

54. The 4 Testing Steps 1. Select what has to be measured
Analysis: Completeness of requirements
Design: tested for cohesion
Implementation: Code tests
2. Decide how the testing is done
Code inspection
Proofs (Design by Contract)
Black-box, white box,
Select integration testing strategy (big bang, bottom up, top down, sandwich)
3. Develop test cases
A test case is a set of test data or situations that will be used to exercise the unit (code, module, system) being tested or about the attribute being measured
4. Create the test oracle
An oracle contains of the predicted results for a set of test cases
The test oracle has to be written down before the actual testing takes place

55. Guidance for Test Case Selection
Use analysis knowledge about functional requirements (black-box testing):
Use cases
Expected input data
Invalid input data
Use design knowledge about system structure, algorithms, data structures (white-box testing):
Control structures
Test branches, loops, ...
Data structures
Test records fields, arrays, ...
Use implementation knowledge about algorithms:
Examples:
Force division by zero
Use sequence of test cases for interrupt handler

56. Testing Activities Unit T est Unit T est Integration Functional Test
Requirements
Analysis
Document
Subsystem
Code
Unit
Requirements
Analysis
Document
System
Design
Document T
est
Tested
Subsystem
User
Manual
Subsystem
Code
Unit T
est
Tested
Subsystem
Integration
Functional
Test
Test
Functioning
System
Integrated
Subsystems
Tested Subsystem
Subsystem
Code
Unit T
est
All tests by developer

57. Testing Activities continued
Client’s
Understanding
of Requirements
Global
Requirements
User
Environment
Validated
System
Accepted
System
Functioning
System
Performance
Acceptance
Installation
Test
Test
Test
Usable
System
Tests by client
Tests by developer
User’s understanding
System in
Use
Tests (?) by user

58. Types of Testing Unit Testing: Integration Testing:
Individual subsystem
Carried out by developers
Goal: Confirm that subsystems is correctly coded and carries out the intended functionality
Integration Testing:
Groups of subsystems (collection of classes) and eventually the entire system
Goal: Test the interface among the subsystem

59. System Testing System Testing: Acceptance Testing:
The entire system
Carried out by developers
Goal: Determine if the system meets the requirements (functional and global)
Acceptance Testing:
Evaluates the system delivered by developers
Carried out by the client. May involve executing typical transactions on site on a trial basis
Goal: Demonstrate that the system meets customer requirements and is ready to use
Implementation (Coding) and testing go hand in hand

60. Unit Testing Informal: Static Analysis: Dynamic Analysis:
Incremental coding
Static Analysis:
Hand execution: Reading the source code
Walk-Through (informal presentation to others)
Code Inspection (formal presentation to others)
Automated Tools checking for
syntactic and semantic errors
departure from coding standards
Dynamic Analysis:
Black-box testing (Test the input/output behavior)
White-box testing (Test the internal logic of the subsystem or object)
Data-structure based testing (Data types determine test cases)

61. Unit-testing Heuristics
1. Create unit tests as soon as object design is completed:
Black-box test: Test the use cases & functional model
White-box test: Test the dynamic model
Data-structure test: Test the object model
2. Develop the test cases
Goal: Find the minimal number of test cases to cover as many paths as possible
3. Cross-check the test cases to eliminate duplicates
Don't waste your time!
4. Desk check your source code
Reduces testing time
5. Create a test harness
Test drivers and test stubs are needed for integration testing
6. Describe the test oracle
Often the result of the first successfully executed test
7. Execute the test cases
Don’t forget regression testing
Re-execute test cases every time a change is made.
8. Compare the results of the test with the test oracle
Automate as much as possible

62. Test Stubs and Drivers
A test driver simulates the part of the system that calls the component under test.
A test stub simulates components that are called by the tested component and must return a value compliant with the return result type of the method’s type signature
Driver
Program to
be tested
Stub

63. Integration Testing Strategy
The entire system is viewed as a collection of subsystems (sets of classes) determined during the system and object design.
The order in which the subsystems are selected for testing and integration determines the testing strategy
Big bang integration (Nonincremental)
Bottom up integration
Top down integration
Sandwich testing
Variations of the above
For the selection use the system decomposition from the System Design

64. Example: Three Layer Call HierarchyB C D G F E
Layer I
Layer II
Layer III

65. Integration Testing: Big-Bang Approach
Unit Test A
Don’t try this!
System Test
Unit Test B
Unit Test C
Unit Test D
Unit Test E
Unit Test F

66. Bottom-up Testing Strategy
The subsystem in the lowest layer of the call hierarchy are tested individually
Then the next subsystems are tested that call the previously tested subsystems
This is done repeatedly until all subsystems are included in the testing
Special program needed to do the testing, Test Driver:
A routine that calls a subsystem and passes a test case to it
SeatDriver (simulates VIP)
Seat Interface
(in Vehicle Subsystem)
Seat Implementation
Stub Code
Real Seat
Simulated
Seat (SA/RT)

67. Bottom-up IntegrationC D G F E
Layer I
Layer II
Layer III
Test E
Test B, E, F
Test
A, B, C, D,
E, F, G
Test F
Test C
Test D,G
Test G

68. Pros and Cons of bottom up integration testing
Bad for functionally decomposed systems:
Tests the most important subsystem (UI) last
Useful for integrating the following systems
Object-oriented systems
real-time systems
systems with strict performance requirements

69. Top-down Testing Strategy
Test the top layer or the controlling subsystem first
Then combine all the subsystems that are called by the tested subsystems and test the resulting collection of subsystems
Do this until all subsystems are incorporated into the test
Special program is needed to do the testing, Test stub :
A program or a method that simulates the activity of a missing subsystem by answering to the calling sequence of the calling subsystem and returning back fake data.

70. Top-down Integration TestingB C D G F E
Layer I
Layer II
Layer III
Test
A, B, C, D,
E, F, G
All Layers
Test A
Test A, B, C, D
Layer I + II
Layer I

71. Pros and Cons of top-down integration testing
Test cases can be defined in terms of the functionality of the system (functional requirements)
Writing stubs can be difficult: Stubs must allow all possible conditions to be tested.
Possibly a very large number of stubs may be required, especially if the lowest level of the system contains many methods.
One solution to avoid too many stubs: Modified top-down testing strategy
Test each layer of the system decomposition individually before merging the layers
Disadvantage of modified top-down testing: Both, stubs and drivers are needed

72. Sandwich Testing Strategy
Combines top-down strategy with bottom-up strategy
The system is view as having three layers
A target layer in the middle
A layer above the target
A layer below the target
Testing converges at the target layer
How do you select the target layer if there are more than 3 layers?
Heuristic: Try to minimize the number of stubs and drivers

73. Sandwich Testing StrategyB C D G F E
Layer I
Layer II
Layer III
Test E
Test B, E, F
Bottom
Layer
Tests
Test F
Test
A, B, C, D,
E, F, G
Test G
Test D,G
Test A,B,C, D
Test A
Top
Layer
Tests

74. Pros and Cons of Sandwich Testing
Top and Bottom Layer Tests can be done in parallel
Does not test the individual subsystems thoroughly before integration
Solution: Modified sandwich testing strategy

75. Modified Sandwich Testing Strategy
Test in parallel:
Middle layer with drivers and stubs
Top layer with stubs
Bottom layer with drivers
Top layer accessing middle layer (top layer replaces drivers)
Bottom accessed by middle layer (bottom layer replaces stubs)

76. Modified Sandwich Testing Strategy
Double
Test I
Test A,C A B C D G F E
Layer I
Layer II
Layer III
Test F
Test E
Test B
Test B, E, F
Triple
Test I
Test D,G
Double
Test II
Test
A, B, C, D,
E, F, G
Test G
Test D
Test A
Test C

77. Scheduling Sandwich Tests: Example of a Dependency Chart
SystemTests
Unit Tests
Double Tests
Triple Tests

78. Steps in Integration-Testing
1. Based on the integration strategy, select a component to be tested. Unit test all the classes in the component.
2. Put selected component together; do any preliminary fix-up necessary to make the integration test operational (drivers, stubs)
3. Do functional testing: Define test cases that exercise all uses cases with the selected component
4. Do structural testing: Define test cases that exercise the selected component
5. Execute performance tests
6. Keep records of the test cases and testing activities.
7. Repeat steps 1 to 7 until the full system is tested.
The primary goal of integration testing is to identify errors in the (current) component configuration. .

79. Which Integration Strategy should you use?
Factors to consider
Amount of test harness (stubs &drivers)
Location of critical parts in the system
Availability of hardware
Availability of components
Scheduling concerns
Bottom up approach
good for object oriented design methodologies
Test driver interfaces must match component interfaces
...
Detection of design errors postponed until end of testing
Top down approach
Test cases can be defined in terms of functions examined
Need to maintain correctness of test stubs
Writing stubs can be difficult
...Top-level components are usually important and cannot be neglected up to the end of testing

80. System Testing Functional Testing Structure Testing
Performance Testing
Acceptance Testing
Installation Testing
Impact of requirements on system testing:
The more explicit the requirements, the easier they are to test.
Quality of use cases determines the ease of functional testing
Quality of subsystem decomposition determines the ease of structure testing
Quality of nonfunctional requirements and constraints determines the ease of performance tests:

81. Essentially the same as white box testing.
Structure Testing
Essentially the same as white box testing.
Goal: Cover all paths in the system design
Exercise all input and output parameters of each component.
Exercise all components and all calls (each component is called at least once and every component is called by all possible callers.)
Use conditional and iteration testing as in unit testing.

82. Essentially the same as black box testing
Functional Testing
Essentially the same as black box testing
Goal: Test functionality of system
Test cases are designed from the requirements analysis document (better: user manual) and centered around requirements and key functions (use cases)
The system is treated as black box.
Unit test cases can be reused, but in end user oriented new test cases have to be developed as well. . .

83. Performance Testing Timing testing Stress Testing Environmental test
Stress limits of system (maximum # of users, peak demands, extended operation)
Volume testing
Test what happens if large amounts of data are handled
Configuration testing
Test the various software and hardware configurations
Compatibility test
Test backward compatibility with existing systems
Security testing
Try to violate security requirements
Timing testing
Evaluate response times and time to perform a function
Environmental test
Test tolerances for heat, humidity, motion, portability
Quality testing
Test reliability, maintain- ability & availability of the system
Recovery testing
Tests system’s response to presence of errors or loss of data.
Human factors testing
Tests user interface with user

84. Test Cases for Performance Testing
Push the (integrated) system to its limits.
Goal: Try to break the subsystem
Test how the system behaves when overloaded.
Can bottlenecks be identified? (First candidates for redesign in the next iteration
Try unusual orders of execution
Call a receive() before send()
Check the system’s response to large volumes of data
If the system is supposed to handle 1000 items, try it with 1001 items.
What is the amount of time spent in different use cases?
Are typical cases executed in a timely fashion?

85. Acceptance Testing
Goal: Demonstrate system is ready for operational use
Choice of tests is made by client/sponsor
Many tests can be taken from integration testing
Acceptance test is performed by the client, not by the developer.
Majority of all bugs in software is typically found by the client after the system is in use, not by the developers or testers. Therefore two kinds of additional tests:
Alpha test:
Sponsor uses the software at the developer’s site.
Software used in a controlled setting, with the developer always ready to fix bugs.
Beta test:
Conducted at sponsor’s site (developer is not present)
Software gets a realistic workout in target environ- ment
Potential customer might get discouraged

86. Testing has its own Life Cycle
Establish the test objectives
Design the test cases
Write the test cases
Test the test cases
Execute the tests
Evaluate the test results
Change the system
Do regression testing

87. Test Team Test Team Professional Tester Analyst System Designer User
too familiar
Programmer
with code
Analyst
System
Designer
Test
User
Team
Configuration
Management
Specialist

88. Summary
Testing is still a black art, but many rules and heuristics are available
Testing consists of component-testing (unit testing, integration testing) and system testing
Design Patterns can be used for integration testing
Testing has its own lifecycle