1. CHAPTER 2 Testing Throughout the Software Life Cycle
The University of Lahore
A “W4” Category University
Lecture 8
CHAPTER 2
Testing Throughout the Software Life Cycle
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2. The University of Lahore
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Chapter Contents
Commonly applied software development models.
Test levels
Test types
How maintenances influences the test process, levels and types
How testing can be organized
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3. The University of Lahore
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4. The University of Lahore
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manifest
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5. The University of Lahore
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Waterfall Model
Waterfall model is a model in which tasks are executed in sequential fashion.
We starts at the top of the waterfall with the requirements and flow down through the various tasks finishing with implementation into live environment.
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6. The University of Lahore
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7. REVIEW The University of Lahore Requirements (What is requirement?)
A “W4” Category University
REVIEW
Requirements (What is requirement?)
Carry out the preliminary study of the situation
Decide exactly what the problem is?
Feasibility Study
Cost analysis
Decide whether or not to continue with the project?
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8. The University of Lahore
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Analysis
Study the existing system in detail is called analysis.
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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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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Construction & Testing
Coding (any new program have to be written)
System testing. Test data is designed and the results are forecast
Acceptance testing. The users of the new system check it
user documentation is prepared
Technical documentation is prepared
users are trained to use the new system
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Implementation - Conversion
File conversion
Software and hardware installation
System conversion
System Maintenance and Review
Keep watching on the new system
Repair faults in both hardware and software
Upgrade the system as requirements change
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12. The University of Lahore
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Problems/Challenges associated with Waterfall Model
Testing tends to happen towards the end of the project life cycle, so defects are detected close to the live implementation date.
Difficult to carry out numerous alterations for a particular phase.
One phase has to be complete before moving onto the next phase.
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13. The University of Lahore
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Partitioning of the project into different stages makes it difficult to respond to changing customer requirements.
Unrealistic to expect accurate requirements so early in the project
Therefore, this model is only appropriate when
the requirements are well-understood
The changes will be limited during the design process.
Few business systems have stable requirements.
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14. The University of Lahore
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Advantages of Waterfall Model
Most common
Simple to understand and use
Easy to manage
Phases are processed and completed individually
where requirements are well understood
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15. The University of Lahore
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V - Model
The V-model is a model that illustrates how testing activities (verification and validation) can be integrated into each phase of the life cycle.
3 Levels of V-Model
Procedure (What has to be done?)
Methods (How the tasks are to be performed?)
Tool Requirements (What is to be used to carry out the tasks?)
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16. The University of Lahore
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The V-Model is structured into four
functional parts, called submodels.
Project Management (PM) tasks
The PM submodel states that the staff members should participate in all activities.
Plans, controls and informs the SD, QA and CM submodels.
Job selection activity
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Software/System Development (SD)
Develops the software/system
Big emphasis on Commercial Off The Shelf soft wares
COTS must be given special attention.
Quality Assurance (QA)
Access the product or software
Compares the product or software with the plans and requirements.
It suggest improvements if the product is rejected
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18. The University of Lahore
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Configuration Management (CM)
Administrates the product generated
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19. The University of Lahore
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V - Model
Test Level
“A group of test activities that are organized and managed together in V-Model.”
Types of Test Levels
Component Testing
Integration Testing
Acceptance Testing
System Testing
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20. The University of Lahore
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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 behaviour of the whole system/product.
Acceptance Testing
Validation testing with respect to user needs, requirements and expectations.
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21. Verification & Validation
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Verification & Validation
Verification
Have you built the product right?
Does the product meet system specification?
Validation
Have you built the right product?
Does the product meet user expectations?
It is possible that a software application may fulfill its specification but it may deviate from users expectations or their desired behaviour. That means, software is verified but not validated.
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22. Verification & Validation
The University of Lahore
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Verification & Validation
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23. Verification & Validation
The University of Lahore
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Verification & Validation
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24. The University of Lahore
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V - Model
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25. The University of Lahore
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V - Model
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26. The University of Lahore
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V - Model
Represent testing where system is validated
Specifications or requirements
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27. The University of Lahore
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Comparisons
Waterfall Vs V-Model
Waterfall Model
V-Model
the start of the next phase will occur at the completion of the previous phase.
development and testing processes will occur simultaneously to save the time as well as money.
the output of each phase will become input to the next phase.
verification we can also do the validations.
we can't go back in the waterfall model.
We can design the test case for acceptance test when requirement phase is carried out and so on……
If any defect you can identify the risk, time and cost of the s/w is very high.
If any defect you can identify risk, cost and time of the s/w is very low.
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