CH02.L01. SWDLC
Summary
TLDRThis script delves into software testing within the Software Development Life Cycle (SDLC), exploring various models like the sequential, iterative, and incremental approaches. It emphasizes the importance of testing at different stages and the role of ISO 12207 in standardizing SDLC models. The script contrasts the traditional Waterfall model with the V-model, highlighting their advantages and limitations. It also discusses the iterative model's flexibility and the incremental model's structured approach, including prototyping and agile development. The distinction between verification and validation testing is clarified, with verification ensuring requirements are met, and validation confirming customer needs are satisfied.
Takeaways
- 📚 The chapter discusses the integration of testing throughout the Software Development Life Cycle (SDLC) and its importance in different development stages.
- 🔍 Testing levels and types are introduced, highlighting their application in ensuring software quality before delivery to customers.
- 🔧 Maintenance testing is emphasized as a crucial final stage to identify and fix bugs post-deployment, ensuring ongoing software reliability.
- 🌐 The testing phase is not a separate entity but an integral part of the SDLC, with execution methods varying based on the chosen development model.
- 📈 ISO 12207 is identified as the standard that compiles rules and models for software development, providing a unified reference for selecting and applying SDLC models.
- 🛠️ The Sequential Model, including the Waterfall and V-Model, is explained, detailing their phases and the sequential nature of development and testing.
- 💡 Advantages of the Waterfall Model include simplicity, clear phase requirements, and suitability for small projects with specific goals.
- 🚧 Disadvantages include inflexibility in making modifications and high risk due to late visibility of the working program.
- 🌟 The V-Model is presented as an improvement over the Waterfall Model, with integrated testing phases that allow for earlier defect discovery and resolution.
- 🔄 The Iterative Model is described, allowing for overlapping development and testing cycles, providing flexibility and early customer feedback.
- 📈 The Incremental Model combines elements of both Sequential and Iterative approaches, enabling phased development and testing of software modules.
- 📌 Verification and Validation Testing are distinguished, with Verification ensuring requirements are met, and Validation confirming customer needs are satisfied.
Q & A
What is the main focus of Chapter 2 in the transcript?
-The main focus of Chapter 2 is on the testing phase within the software development life cycle (SDLC), including different software development models, their execution stages, and how testing is integrated into these stages.
What does SDLC stand for and why is it significant in software development?
-SDLC stands for Software Development Life Cycle. It is significant because it represents the process of developing, testing, and deploying a software product, and it helps in choosing the correct model for software development.
What is the ISO 12207 standard mentioned in the transcript?
-ISO 12207 is a standard that gathers all the rules and standards for software engineers working in the field of software development, including the SDLC models that are chosen and applied during software development.
What are the three software development models discussed in the transcript?
-The three software development models discussed are the sequential model, the iterative model, and the incremental model.
What is the Waterfall model and how does it differ from other models?
-The Waterfall model is a sequential model where each phase of software development is completed before moving on to the next. It differs from other models in that it does not allow for iteration or going back to previous phases once they are completed.
What is the V-model and how does it address the weaknesses of the Waterfall model?
-The V-model is a variation of the Waterfall model that includes testing activities for each phase of development. It addresses the weaknesses of the Waterfall model by allowing for testing to begin as soon as the coding phase is reached, thus identifying defects earlier in the development process.
What are the advantages of the V-model over the Waterfall model?
-The V-model's advantages include the ability to start testing earlier in the development process, which helps to identify and fix defects earlier, leading to higher project success rates and lower costs for defect fixing.
What is the iterative model and how does it differ from sequential models?
-The iterative model divides the software life cycle into smaller cycles, allowing for requirements analysis, design, and coding to be repeated. It differs from sequential models by enabling work to start on new parts of the project without waiting for the completion of previous phases.
What is the incremental model and how does it combine elements of sequential and iterative models?
-The incremental model is a blend of sequential and iterative approaches, where all requirements are divided into parts and developed through multiple cycles, with each cycle resulting in a working module that adds to the final software product.
What is the difference between verification testing and validation testing?
-Verification testing checks if the software meets the initially required specifications, while validation testing assesses whether the software satisfies the customer's needs after confirming that it meets the requirements.
Why is the iterative incremental model beneficial in software development?
-The iterative incremental model is beneficial because it allows for continuous feedback and improvement, enabling developers to create and test modules incrementally, ensuring that each part of the software meets both the specified requirements and the customer's needs.
Outlines
🔍 Introduction to Software Testing in SDLC
This paragraph introduces Chapter 2, focusing on software testing throughout the software development life cycle (SDLC). It emphasizes that testing is not a separate phase but an integral part of the development process. The chapter will explore different software development models, their execution stages, and how testing is conducted at each stage. The goal is to understand the various testing levels and types that software must pass. The ISO 12207 standard, which includes all SDLC models, is mentioned as a key reference for choosing the correct model. The paragraph also discusses the sequential model, particularly the waterfall model, and its advantages and disadvantages.
🌟 Exploring the V-Model and Iterative Models
The second paragraph delves into the V-model, which is an improvement over the waterfall model. It explains that the V-model is divided into three parts: development phases, testing phases, and work products. The model allows for testing activities to be planned and executed concurrently with development, enabling earlier detection and resolution of defects. The paragraph also discusses the advantages of the V-model, such as simplicity, time-saving, and early defect detection, as well as its disadvantages, including inflexibility and the need for updates to testing documents during modifications. The iterative model is introduced as a way to break down the software life cycle into smaller cycles, allowing for continuous testing and feedback. The paragraph concludes with a brief mention of the integrative model, which combines elements of both sequential and iterative approaches.
🖌️ Iterative Incremental Model and Testing Types
The third paragraph discusses the iterative incremental model, which blends sequential and iterative approaches. It explains that this model involves dividing requirements into parts and developing them through multiple cycles, with each cycle resulting in a working module. The paragraph uses the example of painting the Mona Lisa to illustrate how the model works, emphasizing the importance of customer feedback and iterative improvements. The paragraph also distinguishes between verification testing and validation testing, explaining that verification tests check if the software meets initial requirements, while validation tests ensure the software satisfies the customer's needs. The V-model is highlighted as an example where these testing types are crucial.
Mindmap
Keywords
💡Software Life Cycle
💡Software Development Models
💡Testing Phase
💡Maintenance Testing
💡SDLC (Software Development Life Cycle)
💡ISO 12207
💡Sequential Model
💡V-Model
💡Iterative Model
💡Incremental Model
💡Verification Testing
💡Validation Testing
Highlights
Introduction to chapter 2 focusing on testing throughout the software development life cycle.
Exploration of different software development models and their execution stages in relation to testing.
Discussion on the importance of testing levels and types in software development.
Introduction to maintenance testing and its role after software delivery.
Understanding the integration of the testing phase within the software development cycle.
Explanation of the ISO 12207 standard and its significance in software development models.
Overview of sequential models, including the waterfall and V-model.
Advantages and disadvantages of the waterfall model in software development.
Introduction to the V-model and its structure for addressing waterfall model limitations.
The concept of testing activities in the V-model corresponding to development phases.
Explanation of work products in the V-model and their testing counterparts.
Advantages of the V-model, including early defect discovery and cost-effectiveness.
Disadvantages of the V-model, particularly regarding flexibility and prototype availability.
Introduction to the iterative model and its approach to software development.
Description of the iterative incremental model blending sequential and iterative approaches.
Examples of the iterative incremental model, including prototyping and RAD.
The importance of verification and validation testing in the development process.
Differentiation between verification testing and validation testing.
Transcripts
We will start chapter 2 which tackles
testing throughout software life Cycle
and through which we will know about the different
software development in models and their execution stages
and to see how the testing takes place
and in which stage of our software developing.
After that we will be introduced to the testing levels
and types that we apply on the software
and finally we will talk about the maintenance testing
which comes at the last stage after
after finishing our software developing
and deliver it to the customer to start working live.
In this stage we will check if there are bugs or problems
after using it or not, and to fix them as soon as they are discovered
to guarantee our software quality
and that it is running with the fewest number
of bugs in the real environment
By the end of Ch 2, we should have understood completely
all the test levels and types that
any software has to pass.
Lets agree first
that the testing phase itself is not a separate phase from the
software development cycle or model
but actually it is a basic part that occurs during it
however, the way of its execution is the different from one model to another
and that depends on t he type of the software developing model
which will be chosen and the way it can be
applied and executed.so all our focus in this chapter
will be on the testing phase
inside the software's developing life cycle
which is abbreviated to SDLC and
how it is applied inside the module
where SDLC came from and what its sources
to know how to choose the correct model from them
these models exist in the ISO
standard 12207. T he ISO is
the organization that gathered and put
all the rules and standards for the software engineers working in
the field of software developement
Also it gathered all the SDLC models
which are chosen and applied in case of developing
any software. As a result it became the
unified main reference which we follow to choose
the model and to apply it, to avoid being random in
the applying and execution and to be working
according the standard.
let`s talk about software development models
we have take in our consideration that although
each model has its fixed and specified phases of apply
but its execution in a project differs from
the other according to the project's goals
and objectives
There are many types for the software development models,
here in the course and according to "IS2qb"
we will concentrate on three of them
sequential models, iterative model,
and the incremental model.
1: The sequential model , in which the phases of the software development
take place in a sequential that means
each phase ends it calls the phase after it
examples of this kind are waterfall and V-model
that appeared after that time. First, the waterfall model
which consists of some phases that are executed sequentially
the way this model is applied
depends on finishing
each phase separately
before starting another phase
for ex, if we are in the phase of specifying the user requirements, i`ll not
be able to start the next phase which is the design phase
before gathering all the requirements related to the project
and studying them all and getting them approved from the client
what are the advantages and the disadvantages of applying the waterfall model
for the advantages as following
First, it is easy to use and apply
Second, we will find each phase has its
own specific requirements and specific way to be reviewed
Therefore, I know in every phase what is required and what should be delivered
For ex, if we are in the phase of requirements gathering
then i should deliver the requirements document after finishing
and also should be reviewed
Each phase is fully executed
before starting other phases
This model suits more the small projects
that clearly have specific goals
As for its disadvantages:
the difficulty to set any modification
during executing the project, and this is because
during the project we will not be able to return back to change
the requirements because i have already finished
the phase of the analysis and
gathering for all our requirements and started the execution.
Another thing is the complexity of transferring from a phase to another
results a very high risk
because i can`t see my program working unless
in the last phase when it is fully finished
therefore, I have to wait till its finished to see the project
complete and working, This is the reason
another model was raised called the v-model, which fixes
the weak points we have faced in the waterfall model
The v-model is divided to
3 parts. the first on the left side we will find exactly
like the waterfall which begins with the user requirements
the software specifications,
high level design, and the low level design
till we reach the coding phase
The right side concentrates on testing
activities that are planned for during
each phase of the developments phases
to begin testing directly after reaching the coding phase
and they are the component or the unit test,
integration test, system test, and
acceptance test. Note that when it comes to the practical applying
We will be able to shrink or extend
the model levels whether in testing
or in development according to the project
we are working on ,like what ? We may
find examples for projects that include a phase called component
integration testing after the component testing phase
or we may find system integration
testing after system testing phase so it
is highly expected to increase or decrease according the project we are working on.
The third part is relating to the work products
which consists of
the output of each phase of the development phase
which we will test using a specific
testing activity, like what ?
For ex, in the phase of gathering the requirements in
the development cycle. we will notice that it meets
the acceptance testing activity on the other side,
in which a planning for the acceptance testing
against the requirement specification
Then after finishing the software and before its
delivery we will execute all the acceptance
testing work that we have prepared
during gathering the requirements to check if
the system achieves them or not after being completed, and
if the customer will be satisfied with it or not. Now we can understand that for
every development phase, there is another testing phase facing it, in which
we plan for the testing we will run when
we reach that phase. That is because when
reaching the coding phase, we will begin executing the plan with
the default testing. That means to prepare
the testing tasks for each phase to avoid wasting
time when executing and also
to achieve its goals. And this is through the 5 phases
and that have equivalent phases like
acceptance test planning, system test planning,
integration test planning, unit
test planning and finally the coding phase. This is for
the work products use in the v-model. We can
increase our knowledge about them by
checking the generic work products, that their
reference is ISO12207
and the CMMI
( Capability Maturity Model Integration )
you will find all the generic
products we may need in any project.
We said before that the v-model was raised
to avoid the waterfall model disadvantages, but what about its advantages :
It is simple in using and applying specially in
the small projects.Also, it saves time
as instead of waiting to test in the last
phase of the software development and
until the software is fully completed as in waterfall,
here we begin preparing for the testing
activities earlier from the requirements phase
till reaching the coding phase.
This helps to discover
the defects in an earlier phase and get them fixed earlier,
to apply the earlier testing principle.
As a result the project success percentage and the percentage to complete it on time
is high, in addition to the costs of fixing
the defects are cheaper in the early phases of the project.
Regarding its disadvantages , we will notice that if there
is any modification during the project,we
will need to update all
the testing documents with the requirements because
as any modification will have effect on the rest of the project,
So although it is easily used,
but it misses the flexibility. Although, we plan and prepare for each
development phase,
testing document, and although
this helps us in discovering
the defects, but we always need to
wait for the implementation phase to start
writing the code, and this also will deprive me from having
any prototype from which I can get the customer feed
before the delivery. And this was a simple idea about
the v-model . we will talk about the integrative model
that depends on dividing the software
life cycle to a group of smaller life cycles that
begins with the requirements analysis and design an finalizes with coding,
We repeat these processes and that`s why we call it iterative model,
so we don't have to wait
for a full phase to be finished before
starting another one.
As a result, we will find that in each
iteration, a group of tasks take place in the same phase,
then we will find that we are testing
repeatedly during each iteration before
reaching the final product. As long as each
time we work for a part and then we add to it
or modify within it, so we have
to run a regression test immediately to know if these
modifications affected the rest of the modules or not.
Note that , in this model it not a must to
have all the requirements, but on
contrary you can begin with
a simple group of requirements and then increase them
during the development. The
Mona Lisa painting is a simple example for
applying the iterative model, if a customer
asked for drawing the Mona Lisa without giving any
details, Here the requirements is not complete,
in this phase we understood the required
requirements that are incomplete. We made
an initial design and applied it, and then we got
the result, which in picture No1.
Then we let the customer see the picture to know his opinion,
if we should add new requirements, and
what required modifications needed for the first version of results we have.
So we will make another iteration with the new changes and modifications on the picture
no1 and keep repeating this process
till reaching the last shape of the product exactly like how
the customer needs that is in picture No3.
The third type of models is
the iterative incremental model that is a
blend of both the sequential and the iterative
what does it mean? In this model we will have all the requirements
but we will divide them for parts, we
will execute them by multiple development cycle,
as if each small cycle results a module, which is
acts as full working part of the requirements. After finishing
each part we will run his required tests.
and you keep repeating these cycles that
means iterations, and within each time we take
a new part of the requirements and finish it and then
add as a module for the preceded one
till reaching the final software that
the customer needs. The most famous examples for
the iterative incremental model are the prototyping, the rapid
application development or the RAD,
rational unified process or RUP , and
the agile development models. Let`s return back
again for the Mona Lisa Painting but in this time
instead of each time we get the initial shape of the picture and then
modify on it till reaching the last required shape,
we will devide the picture for parts and each time
we will not begin a new part until finishing the current one first.
And so on, meaning that we will advance phase by phase and
at the beinging of each part we will add new part of
the requirements and finish its tests then we will let
the customer see it and take feedback. We will keep
repeating this till reaching exactly what he needs.
There are some important things that will be with us in all
the phases of development that are
the verification testing and
validation testing, and the most famous
example for them is the V-model,
the letter (v) here means verification and validation
but what is the difference between them?
we will find that the verification test answers the question “does
the software meets
the requirements that was initially required
or not ?” because it`s highly expected that
the final version of the software has more than required
in the initially agreed upon requirements, it`s
also expected that we missed a specific
requirement in our software, so we have always
to verify the requirements, but about
the Validation testing we use it to answer a more important question
which is whether “after confirming that the software
meets the requirements, does it satisfy
the customer's needs or no? ” , we may find that
the software is totally not what
the customer needs, especially in the
V-model in which we can`t judge if
the software fulfills the customer
needs unless it finishes because it is
sequentially. Finally let`s say again that
the verification testing cares about the requirements but
the validation testing cares about achieving
the customer business needs.
浏览更多相关视频
Lecture 09: Waterfall Derivatives
SE 12 : All SDLC Models Revision | Software Engineering Full Course
Comparison of All SDLC Models | Waterfall, Iterative, Prototype, Spiral, Increment, RAD, Agile etc.
V Shaped Model with examples | SDLC | Software Engineering
Lecture 07: Life Cycle Model (Contd.)
Lecture 11: Evolutionary Model
5.0 / 5 (0 votes)