1. CS-4349 Software Testing & Implementation
The University of Lahore
A “W4” Category University
CS-4349 Software Testing & Implementation
Lecture 4
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2. The University of Lahore
A “W4” Category University
1.1.5 Testing and quality
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3. What is root-cause analysis?
The University of Lahore
A “W4” Category University
1.1.5 Testing and quality
What is root-cause analysis?
To find real reason when we detect faults is called root cause analysis.
When we detect failures, we might try to track them back to their root cause, the real reason that they happened.
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4. Exercise The University of Lahore Root Cause Analysis
A “W4” Category University
1.1.5 Testing and quality
Exercise
Root Cause Analysis
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5. The University of Lahore
A “W4” Category University
1.1.5 Testing and quality
Q 1- What can be the ways of carrying root cause analysis?
Way1: __________________________________________________________
Way2: __________________________________________________________
Q 2- An organization has a problem with printing repeatedly failing. Suggest some possible causes of this failure.
Cause 1: ____________________________________________________
Cause 2: ____________________________________________________
Cause 3: ____________________________________________________
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6. The University of Lahore
A “W4” Category University
1.1.5 Testing and quality
Q 3- These causes may happen because
__________________________________________________________
Q 4- What possible steps the software testers will take to design the software and resolve the printing failure and facilitate the users?
____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
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7. The University of Lahore
A “W4” Category University
1.1.5 Testing and quality
Q-1 What are the ways of carrying root-cause analysis?
Discussion
Involving group of people with brainstorming ideas
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8. The University of Lahore
A “W4” Category University
1.1.5 Testing and quality
Q-2
Suppose an organization has a problem with printing repeatedly failing. Some IT maintenance will sit together to examine the problem and they start by brainstorming all the possible causes of the failure.
Some of the cause they discover might be:
Printer runs out of supplies (ink or paper)
Printer driver software fails.
Printer room is too hot for the printer.
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9. The University of Lahore
A “W4” Category University
1.1.5 Testing and quality
Q-3
If we look at one of the causes “ printer runs out of
supplies, it may happen because:
ROOT CAUSE:
No one is responsible for checking printer ink/paper before use.
Staff not trained in looking after the printer.
No process for stock control and ordering.
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10. Summary The University of Lahore
A “W4” Category University
1.1.5 Testing and quality
Summary
Root-cause analysis is an important aspect of quality assurance activities and testing contributes by helping us to identify defect and improve software quality as early as possible before the software is in use.
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11. The University of Lahore
A “W” Category University
Ranked Amongst The Top 550 Universities of The WORLD!
1.1.6 How much testing is enough?
How much testing should we do?
Test everything
Test nothing
Test some of the software
Exhaustive Testing
A test approach in which the test suit comprises all combinations of input values and preconditions.
Testing Principle-Exhaustive testing is impossible
Testing everything is not feasible/possible.
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12. The University of Lahore
A “W” Category University
Ranked Amongst The Top 550 Universities of The WORLD!
1.1.6 How much testing is enough?
EXAMPLE 1
How many tests would you need to do to completely test a one-digit numeric field?
10 possible valid numeric values (10 tests)
We need to ensure that all invalid values are rejected.
e.g. 26 uppercase letters, 26 lowercase letters, special characters and blank space. Total tests would be 68.
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13. The University of Lahore
A “W” Category University
Ranked Amongst The Top 550 Universities of The WORLD!
1.1.6 How much testing is enough?
EXAMPLE 2
One screen has 15 input fields, each having 1 digit numeric field. How many test are required to do?
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14. The University of Lahore
A “W4” Category University
1.1.6 How much testing is enough?
How much testing should we do?
Test everything
Test nothing
Test some of the software
Exhaustive Testing
A test approach in which the test suit comprises all combinations of input values and preconditions.
Testing Principle-Exhaustive testing is impossible
Testing everything is not feasible/possible.
20/09/2018

15. The University of Lahore
A “W4” Category University
1.1.6 How much testing is enough?
EXAMPLE 1
How many tests would you need to do to completely test a one-digit numeric field?
10 possible valid numeric values (10 tests)
We need to ensure that all invalid values are rejected.
e.g. 26 uppercase letters, 26 lowercase letters, special characters and blank space. Total tests would be 68.
20/09/2018

16. The University of Lahore
A “W4” Category University
1.1.6 How much testing is enough?
EXAMPLE 2
One screen has 15 input fields, each having 1 digit numeric field. How many test are required to do?
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17. The University of Lahore
A “W4” Category University
1.2 What is testing?
TESTING
“Testing is a process rather than a single activity-there are series of activities involved.”
One of the activities is all life cycle activities. Testing takes place throughout the software development life cycle.
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18. Software Development Life Cycle
The University of Lahore
A “W4” Category University
1.2 What is testing?
Software Development Life Cycle
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19. Software Development Life Cycle (SDLC)
The University of Lahore
A “W4” Category University
1.2 What is testing?
Software Development Life Cycle (SDLC)
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20. The University of Lahore
A “W4” Category University
1.2 What is testing?
SYSTEM LIFE CYCLE
System life cycle is an organizational process of developing and maintaining systems.
It helps in establishing a system project plan.
System development life cycle means combination of various activities put together are referred as system development life cycle.
In the System Analysis and Design terminology, the system development life cycle means software development life cycle.
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21. The University of Lahore
A “W4” Category University
1.2 What is testing?
Phases of software development cycle
Problem Recognition (System Study)
Feasibility Study
System Analysis
System Design
Coding /Implementation/Construction
Testing
Maintenance
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22. The University of Lahore
A “W4” Category University
1.2 What is testing?
System Study
System study is the first stage of system development life cycle.
It gives a clear picture of what actually the physical system is?
System study is done in two phases.
In the first phase, the preliminary survey of the system is done which helps in identifying the scope of the system. The second phase of the system study is more detailed and in-depth study in which the identification of user’s requirement and the limitations and problems of the present system are studied.
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23. The University of Lahore
A “W4” Category University
1.2 What is testing?
After completing the system study, a system proposal is prepared by the System Analyst (who studies the system) and placed before the user.
The proposed system contains the findings of the present system and recommendations to overcome the limitations and problems of the present system in the light of the user’s requirements.
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24. The University of Lahore
A “W4” Category University
1.2 What is testing?
System Study (SUMMARY)
Problem identification and project initiation
Background analysis
Conclusion findings
Carry out the preliminary study of the situation
Decide exactly what the problem is?
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25. The University of Lahore
A “W4” Category University
1.2 What is testing?
Feasibility Study
On the basis of result of the initial study, feasibility study takes place.
The feasibility study is basically the test of its
Workability
Meeting user’s requirements
Effective use of resources
Cost effectiveness
Decide whether or not to continue with the project?
In the process of feasibility study, the cost and benefits are estimated with greater accuracy.
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26. The University of Lahore
A “W4” Category University
1.2 What is testing?
System Analysis
Study the existing system in detail is called analysis.
During analysis, data are collected
Ways to study the existing system
Interview users of the current system
Read any manual or instructions which are in use
Observe the current system in operation
Questionnaires
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27. The University of Lahore
A “W4” Category University
1.2 What is testing?
System Design
Based on the user requirements and the detailed analysis of a new system, the new system must be designed. This is the phase of system designing.
It is a most difficult phase in the development of a system.
Normally, the design proceeds in two stages :
preliminary or general design
Structure or detailed design
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28. The University of Lahore
A “W4” Category University
1.2 What is testing?
Preliminary or general design:
The features of the new system are specified.
The costs of implementing these features and the benefits to be derived are estimated.
Structure or detailed design:
At this stage, the design of the system becomes more structured.
Input, output and processing specifications are drawn up in detail.
In the design stage, the programming language and the platform in which the new system will run are also decided.
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29. Designing The University of Lahore Data capture forms
A “W4” Category University
1.2 What is testing?
Designing
Data capture forms
Type of user interface
Validations methods-how is input data going to be test?
Programs-if some new programs has to be written then they have to be designed at this stage
Input screens
Output screens
System flowcharts
Program flowcharts
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30. The University of Lahore
A “W4” Category University
Coding/Construction
After designing the new system, the whole system is required to be converted into computer understanding language.
This is also called the programming phase in which the programmer converts the program specifications into computer instructions, which we refer as programs. The programs coordinate the data movements and control the entire process in a system.
User documentation is prepared
Technical documentation is prepared
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31. Testing The University of Lahore
A “W4” Category University
Testing
Before actually implementing the new system into operations, a test run of the system is done removing all the bugs, if any.
It is an important phase of a successful system.
After codifying the whole programs of the system, a test plan should be developed and run on a given set of test data.
The output of the test run should match the expected results.
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32. Testing The University of Lahore Unit Testing Integration Testing
A “W4” Category University
Testing
Unit Testing
Integration Testing
System testing. Test data is designed and the results are forecast
Acceptance testing. The users of the new system check it
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33. The University of Lahore
A “W4” Category University
Component Testing
Searches for defects and verifies the functioning of software components (modules, programs, objects, classes etc) that are separately testable.
Integration Testing
Tests interfaces between components, interactions to different parts of a system such as OS, file system and hardware.
System Testing
Concerned with the behavior of the whole system/product.
Acceptance Testing
Validation testing with respect to user needs, requirements and expectations.
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34. The University of Lahore
A “W4” Category University
Implementation
After having the user acceptance of the new system developed, the implementation phase begins.
Implementation is the stage of a project during which theory is turned into practice.
During this phase, all the programs of the system are loaded onto the user's computer. After loading the system, training of the users starts.
File conversion
Software and hardware installation
System conversion
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35. The University of Lahore
A “W4” Category University
Implementation
Main topics of such type of training are:
How to execute the package
How to enter the data
How to process the data (processing details)
How to take out the reports
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36. The University of Lahore
A “W4” Category University
After the users are trained about the computerized system, manual working has to shift from manual to computerized working. The following two strategies are followed for running the system:
Direct Change Over: The old/existing system is immediately removed and the new system come into place
Parallel Run:
In such run for a certain defined period, both the systems i.e. computerized and manual are executed in parallel. This strategy is helpful because of the following:
Manual results can be compared with the results of the computerized system.
Failure of the computerized system at the early stage, does not affect the working of the organization, because the manual system continues to work, as it used to do.
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37. The University of Lahore
A “W4” Category University
Phased/Pilot Run:
In this type of run, the new system is installed in parts. Some part of the new system is installed first and executed successfully for considerable time period. When the results are found satisfactory then only other parts are implemented. This strategy builds the confidence and the errors are traced easily.
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38. The University of Lahore
A “W4” Category University
Maintenance
Maintenance is necessary to eliminate errors in the system during its working life and to tune the system to any variations in its working environment.
It has been seen that there are always some errors found in the system that must be noted and corrected. It also means the review of the system from time to time.
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39. The University of Lahore
A “W4” Category University
System Maintenance and Review
The review of the system is done for:
Knowing the full capabilities of the system
Knowing/upgrade the required changes or the additional requirements
Studying the performance
Keep watching on the new system
Repair faults in both hardware and software
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40. What is Software Testing?
The University of Lahore
A “W4” Category University
What is Testing?
What is Software Testing?
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41. The process of detecting defects is called testing.
The University of Lahore
A “W4” Category University
What is Testing?
The process of detecting defects is called testing.
The process concerned with planning, preparation and evaluation of software products to determine that they satisfy specified requirements.
The process consisting of all life cycle activities, both static and dynamic, concerned with planning, preparation and evaluation of software products and related work products to determine that they satisfy specified requirements, to demonstrate that they are fit for purpose and to detect defects.
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42. Software Testing The University of Lahore
A “W4” Category University
What is Testing?
Software Testing
The process consisting of all life cycle activities, both static and dynamic, concerned with planning, preparation and evaluation of software products and related work products to determine that they satisfy specified requirements, to demonstrate that they are fit for purpose and to detect defects.
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43. The University of Lahore
A “W4” Category University
What is Testing?
Dynamic
Executing the software code to demonstrate the results (Chapter 4)
Static
Without executing software code to find defects. Reviewing of documents including source code. (Chapter 3)
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44. The University of Lahore
A “W4” Category University
What is Testing?
Planning
What we want to do? Report on testing progress, status of the software under test, finalize and close testing when a phase completes. (Chapter 5)
Preparation
We need to choose what testing we’ll do? (Chapter 4)
Evaluation
Executing the test, we must check the results, evaluate the software and completion criteria
Software products and related work products
We test the requirements and design specifications.
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45. The University of Lahore
A “W4” Category University
What is Testing?
Determine that software products satisfy requirements
Checking products against the requirements.
Demonstrate software products fit for purpose
Software does enough to help the users to carry out their tasks. Software does what the user might expected.
Detect Defects
Finding and fixing defects
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46. Software Test and Driving Test Compared
The University of Lahore
A “W4” Category University
Software Test and Driving Test Compared
20/09/2018

47. Software Test and Driving Test Compared
The University of Lahore
A “W4” Category University
Software Test and Driving Test Compared
Activities
Driving Test
Software Test
Planning and Preparation
Static and Dynamic
Evaluation
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48. Software Test and Driving Test Compared
The University of Lahore
A “W4” Category University
Software Test and Driving Test Compared
Activities
Driving Test
Software Test
Determine that they satisfy specified requirements
Demonstrate that they are fit for purpose
Detect defects
20/09/2018

49. Software Test and Driving Test Compared
The University of Lahore
A “W4” Category University
Software Test and Driving Test Compared
Activities
Driving Test
Software Test
Planning and Preparation
1-Which routes to be followed?
2-Time duration
3-Questions to be asked
1-Checking testing progress
2-Status of the software under test
3-Finalize testing when phase completes
4-What testing we will do?
Static and Dynamic
1-Questions to the driver
2-Driving the car
1-Review the software
2-Executing the software
Evaluation
1-Questions
2-Written test
3-Observation during driving
1-Check the results
2-Evaluate the software
3-Completion criteria
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50. Software Test and Driving Test Compared
The University of Lahore
A “W4” Category University
Software Test and Driving Test Compared
Activities
Driving Test
Software Test
Determine that they satisfy specified requirements
1-Checking patience
2-Checking confidence
3-Checking following the rules
4-Checking staring, clutch, gears are properly used by the driver
1-Review the code to check design
2-Review the design to check specifications
Demonstrate that they are fit for purpose
1-Driver is able to drive
1-Software is fit for purpose
Detect defects
1-Finding faults of driver
2-Suggest improvements
1-Finding faults or defects
2-Fixing defects
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51. The University of Lahore
A “W4” Category University
When we can meet our test objectives?
Testing Principle-Early Testing
Testing activities should start as early as possible in the software development and should be focused on defined objectives.
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52. The University of Lahore
A “W4” Category University
When we can meet our test objectives?
Testing Activities
Acceptance testing
Alpha testing
Beta testing or field testing
Component or unit or module
Integration testing
Regression testing
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53. The University of Lahore
A “W4” Category University
Focusing on defects can help us plan our tests
Testing Principle- Defect Clustering
A small number of modules contain most of the defects discovered during testing.
Reasons of defect clustering
1-Code is complex
2-Code is tricky
3-Not reviewing properly during development
4-Early testing is not implemented on time
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54. The University of Lahore
A “W4” Category University
Solution to minimize clustering
Reviewing every module to find defects and failures
Early testing should be implemented on time
Root-cause analysis to prevent defects and failures happening again and again
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55. The defect clusters change over time
The University of Lahore
A “W4” Category University
The defect clusters change over time
Find more defects as the testing improves and then as the defect prevention kicks in, defects numbers dropping
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56. The University of Lahore
A “W4” Category University
Debugging removes defects
Debugging
The process of finding, analyzing and removing causes of failures in the software is called debugging.
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57. The University of Lahore
A “W4” Category University
Debugging Removes Defects
Testing Principle-Pesticide Paradox
If the same tests are repeated over and over again, eventually the same set of tests cases will no longer find any new bugs. To overcome this “Pesticide Paradox”, the test cases need to be regularly reviewed and revised, and new and different tests need to be written to exercise different parts of the software to find more defects.
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58. The University of Lahore
A “W4” Category University
Is the software defects free?
Testing Principle- Testing shows presence of defects
Testing can show that defects are present, but can not prove that there are no defects. Testing reduces the probability of undiscovered defects. If no defects are found, it is not a proof of correctness.
20/09/2018

59. The University of Lahore
A “W4” Category University
If we don’t find defects does that mean the user will accept the software?
Testing Principle- Absence of errors fallacy
Finding and fixing defects does not help if the system built is unusable and does not fulfill the user’s needs and expectations.
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60. The University of Lahore
A “W4” Category University
Testing Principles-SUMMARY
1- Testing shows presence of defects
2- Exhaustive testing is impossible
3- Early testing
4- Defect clustering
5- Pesticide Paradox
6- Testing is context dependent
7- Absence-of-error fallacy
20/09/2018

61. The Psychology of Testing
The University of Lahore
A “W4” Category University
The Psychology of Testing
Independent testing- Who is a tester?
Independence
Separation of responsibilities, which encourages the accomplishment of objective testing.
Level of Independence
Tests by the person who wrote the item under test
Tests by another person within the same team such as another programmer
Tests by a person from a different organizational group
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62. The University of Lahore
A “W4” Category University
The Psychology of Testing
Reviewing and testing Principles
Communicate findings on the product in a neutral, fact-focused way without criticizing the person who created it.
Don’t blame
Be constructive
Say what you liked and what worked, as well as what didn’t work
Don’t be pessimistic (emphasizing the bad part of the situation)
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63. The University of Lahore
A “W4” Category University
The Psychology of Testing
Reviewing and testing Principles
Show what risks have been uncovered and the benefits of review and test
Be polite and helpful, collaborate with your colleagues
Try to understand how the other person feels
Confirm that the other person has understood what you have said and vice versa
Offer you work to be reviewed
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64. Fundamental of Software Testing
The University of Lahore
A “W4” Category University
QUIZ 1 Chapter 1
Fundamental of Software Testing
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65. End of Chapter 1 The University of Lahore A “W4” Category University
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