Software Testing Tutorial #21 - What is Non Functional Testing

Summary

This tutorial explains the fundamentals of non-functional testing, essential for both interviews and practical projects. The video covers the differences between functional and non-functional testing, focusing on key aspects like responsiveness, stability, and performance under varying loads. It also introduces important testing types, including load, stress, soak, volume, and spike testing, with real-world examples such as e-commerce websites. The tutorial helps viewers understand how to evaluate an application's performance, reliability, and robustness in different scenarios, ensuring users can explain these concepts effectively in interviews.

Takeaways

• 📝 Non-functional testing is essential to understand for both project work and interviews, as it helps assess an application's performance, stability, and responsiveness.
• ⚙️ Functional testing checks the features and functionalities based on customer requirements, such as verifying a registration form's behavior.
• ⚡ Non-functional testing evaluates how an application performs under various conditions, such as load, speed, and reliability, focusing on performance metrics like response time and stability.
• ⏳ Response time is a critical part of non-functional testing, ensuring that the application loads and responds within an acceptable timeframe.
• 🚦 Stability testing measures how well an application performs under heavy traffic or load, such as during high-demand events like sales on e-commerce platforms.
• 💡 Performance indicators include response time, processing time, and the ability to handle concurrent users, which all help in determining the application's efficiency.
• 📊 Load testing ensures that the application can handle a specified number of concurrent users without performance degradation.
• 💥 Stress testing pushes the application beyond its limits to determine the point where it breaks or fails under excessive load.
• 🔄 Soak testing examines how an application performs over an extended period with sustained load, ensuring long-term stability.
• 🚀 Spike testing evaluates how an application reacts to sudden and sharp increases in user traffic, testing its resilience under sudden load changes.

Q & A

What is the primary focus of non-functional testing?

Non-functional testing focuses on testing the responsiveness, stability, and performance of an application under different conditions, such as high load or extended usage.

How does functional testing differ from non-functional testing?

Functional testing verifies if the software works according to its functional requirements, such as whether the registration form works correctly. Non-functional testing, on the other hand, evaluates the system's performance, like how fast the registration page loads.

Why is non-functional testing important in an application?

Non-functional testing ensures that the application performs well under different conditions, such as handling high user loads or extended operation times, making sure the application is reliable and responsive.

What are the common performance indicators in non-functional testing?

Common performance indicators include response time, processing time, and concurrent user volume, all of which help assess how the application performs under different conditions.

What is load testing and why is it performed?

Load testing verifies how the application performs under a specific load of users, ensuring that response times are within acceptable limits as defined by the customer.

How is stress testing different from load testing?

Stress testing involves pushing the application beyond its normal load limits to find the breaking point, whereas load testing checks if the application meets performance requirements under expected user load.

What is soak testing, and what is its purpose?

Soak testing involves running the application under a continuous load for an extended period to assess how it behaves over time, ensuring it remains stable under sustained usage.

What aspect of an application does volume testing focus on?

Volume testing examines how an application handles large volumes of data, particularly its database, to ensure the system remains functional as data size increases.

What is spike testing, and when is it used?

Spike testing is used to evaluate how an application reacts to sudden increases and decreases in user load, ensuring it can handle abrupt spikes in traffic without crashing.

What are the key benefits of non-functional testing?

Non-functional testing ensures that an application is reliable, performs well under different conditions, is scalable, and can handle high user loads without compromising response time or stability.

Outlines

00:00

📘 Introduction to Non-Functional Testing

This paragraph introduces non-functional testing, emphasizing its importance in interviews and real-world projects. It explains that understanding non-functional testing helps in distinguishing between functional and non-functional aspects of testing in software. It also highlights that this tutorial will help individuals better understand these concepts, especially if they aim to explain them in interviews. The difference between functional testing, which checks if features meet customer requirements, and non-functional testing, which assesses performance like response time and stability, is introduced.

05:02

⚙️ Key Concepts: Responsiveness and Stability in Non-Functional Testing

This section provides a detailed comparison between functional and non-functional testing using an e-commerce website example. It explains how non-functional testing focuses on aspects like the application's responsiveness and stability under various conditions. The example illustrates how non-functional testing evaluates response times, such as how quickly a registration page loads or how long it takes to complete a process, highlighting the difference from functional tests, which only check if a feature works as expected.

10:04

🔄 Responsiveness and Stability Testing

Here, the focus shifts to the testing of an application's responsiveness and stability, particularly under high load conditions, like during a festive sale on an e-commerce site. It explains how non-functional testing is crucial to ensuring that the application performs well under such circumstances. Key performance indicators such as response time, processing time, and concurrent user volume are introduced as essential factors for verifying the application's performance.

15:05

⏳ Performance Indicators in Non-Functional Testing

This paragraph expands on key performance indicators used in non-functional testing, including response time, processing time, and concurrent user volume. It provides examples of how slow response times during peak user activity can negatively impact user experience. This section also emphasizes the importance of measuring these indicators to ensure the reliability and robustness of an application during high traffic periods.

📊 Types of Non-Functional Testing

The types of non-functional testing are introduced here, including load testing, stress testing, soak testing, volume testing, and spike testing. These are explained as key methods for assessing performance. The section sets up the structure for a deeper dive into each type of test, outlining that these methods ensure the application meets both customer expectations and handles extreme conditions.

💡 Load Testing Explained

Load testing is explained as the process of verifying an application’s performance when it is used by a large number of concurrent users, based on customer requirements. An example is given of using tools to simulate 5000 users accessing an e-commerce website to ensure response times are under 5 seconds. This helps verify if the application can handle the expected user load efficiently.

💥 Stress Testing: Pushing the Limits

Stress testing is described as pushing the application beyond its normal load, gradually increasing the number of users until the application breaks. The goal is to identify the point at which the system crashes, such as when it exceeds 50,000 users. This method helps determine the maximum capacity the application can handle before failing.

⏱️ Soak Testing: Long-Term Load Testing

Soak testing is a form of load testing performed over an extended period. It checks how well an application performs when subjected to a continuous load for several hours or days. The example provided involves 5000 users accessing the system for five days, ensuring that the application can handle prolonged usage without performance degradation.

🗃️ Volume Testing: Database Performance Under Load

Volume testing focuses on the application's database performance when it reaches maximum capacity. It ensures the system can still function effectively as the database fills up. For instance, when an e-commerce site's database reaches its size limit, volume testing assesses how the application behaves under such conditions to prevent crashes or slowdowns.

📈 Spike Testing: Sudden Load Increases

Spike testing examines how an application handles sudden increases and decreases in user load. Unlike load testing's gradual ramp-up, spike testing involves sharp fluctuations in user activity to simulate real-world scenarios, such as a flash sale. This testing evaluates how the application responds to sudden changes and ensures stability despite rapid spikes in usage.

🎯 Non-Functional Testing Summary

The tutorial concludes by summarizing the importance of non-functional testing in verifying an application's reliability and robustness. It highlights that understanding performance indicators and types of testing, such as load, stress, soak, volume, and spike testing, is crucial for both interviews and real-life projects. Non-functional testing ensures that applications perform efficiently under different conditions, safeguarding user experience and system stability.

Keywords

💡Non-functional testing

Non-functional testing refers to the testing of software characteristics such as performance, reliability, and stability, rather than its specific functionalities. In the video, the speaker explains that non-functional testing helps evaluate how the system responds under certain conditions, such as load, stress, and performance.

💡Functional testing

Functional testing involves testing the software's functional requirements, such as specific features and behaviors outlined by the client. In the video, an example of functional testing is the registration process on an e-commerce site, where the functionality of the registration form and user redirection to a dashboard are tested.

💡Response time

Response time refers to how quickly a system reacts to a specific request or operation. In the video, the response time is emphasized as a key performance metric in non-functional testing, such as how long it takes for the registration page to load after clicking a 'Register' button.

💡Stability

Stability measures the consistency of an application's performance, particularly under stress or high user loads. The speaker discusses stability in terms of how well an application continues to perform during peak periods, such as during holiday sales when traffic spikes on e-commerce sites.

💡Load testing

Load testing is a type of non-functional testing that evaluates how an application performs under a specified load, such as handling a large number of users simultaneously. In the video, the speaker explains load testing with an example of 5000 users accessing an e-commerce site, ensuring the response time remains acceptable.

💡Stress testing

Stress testing involves pushing an application beyond its expected load limits to determine at what point the system will fail. In the video, stress testing is described as gradually increasing the number of users beyond the limit (e.g., 50,000 users) to find the breaking point of the application.

💡Soak testing

Soak testing, also known as endurance testing, is performed to evaluate the performance of an application under a sustained load over a long period. The speaker explains how a website's performance is tested over several days with continuous load to see how it behaves over time.

💡Volume testing

Volume testing assesses the system’s ability to handle large amounts of data in its database. The video explains that this type of testing ensures that even as the database grows or becomes full, the application continues to function without performance degradation.

💡Spike testing

Spike testing focuses on how an application performs when it experiences a sudden surge in traffic or usage. In the video, spike testing is described as testing how a system reacts to rapid increases and decreases in the number of users accessing a website, which could mimic real-world scenarios like flash sales.

💡Concurrent user volume

Concurrent user volume refers to the number of users actively using a system at the same time. In non-functional testing, this is important for determining how well the system can handle multiple users simultaneously. The speaker discusses testing scenarios where thousands of users access the site concurrently to measure system performance.

Highlights

Introduction to non-functional testing and its importance in interviews and projects.

Difference between functional and non-functional testing: functional testing tests specific features, while non-functional testing assesses responsiveness and stability.

Explanation of how non-functional testing focuses on the application's performance, such as response time, under specific conditions like load.

Responsiveness and stability are key factors in non-functional testing, especially during high traffic periods (e.g., festive sales on e-commerce websites).

Performance indicators like response time, processing time, and concurrent user volume are crucial in non-functional testing.

Definition and purpose of load testing: verifying if the application performs as expected under a specified number of concurrent users.

Stress testing explained: pushing the system beyond its normal load to determine the breaking point where the application fails.

Soak testing simulates continuous load over an extended period (e.g., days) to ensure the application handles sustained pressure.

Volume testing targets database capacity, assessing how well the application performs as the database fills up.

Spike testing involves sudden increases and decreases in user load to verify how well the system handles these fluctuations.

Non-functional testing verifies the reliability, robustness, and performance of applications under various conditions.

Understanding different non-functional testing methods helps in both interview scenarios and practical project applications.

Tools are used to simulate thousands of concurrent users during load and stress testing.

Explanation of non-functional testing types: load, stress, soak, volume, and spike testing, with examples of how each type is used in real-world scenarios.

Non-functional testing ensures the system can handle high load conditions without crashing or experiencing long response times.

Transcripts

hello everyone welcome again in the

software testing tutorial

we are going to learn non-functional

testing

now understanding non-functional testing

is really important in terms of

interview or even if you are working in

any project you need to have a better

understanding of

what non-functional testing is what are

types of non-functional testing

and why do you need to do non-functional

testing right so because

when you understand all the concepts

then within your project you will be

able to easily

understand what all functional and

non-functional testing is being done

uh when somebody asks you about a

different terms of non-functional

testing and what exactly

that means then you will be able to

explain easily and understand

easily the conversation and discussions

right and if you are

trying to get into the non-functional

testing space

then that this tutorial will help you a

lot to understand

those concepts so that you can explain

those in the

interviews okay so let's uh start the

non-functional testing

prior to that i'll cover briefly about

the functional testing so in the

functional testing in the previous

tutorial we have understood

that functional testing is testing the

functional aspects of

the application or the software so what

are the functional aspects so functional

aspects

are the requirements that you get from

the customer okay say i'll take an

example of e-commerce website again so

e-commerce website

registration functionality registration

functionality is

the feature or the requirement given by

the customer to build

that registration functionality so when

you are testing the registration

functionality you are trying to launch

the registration form provide the

details and click on register link

that testing is the functional testing

now when

we talk about the non-functional testing

non-functional testing

tests the responsiveness and stability

of

the application right so when you are

testing about

uh how the application uh is responding

or how stable the application is

then those aspects are the

non-functional aspects of

the application right so say for example

this is the registration page for

example of an e-commerce website and

this is the link register link right

when i click on register link then it

will open

at the register form wherein i have all

the details of first name last name all

the details and then

i have to click on register button and

once i click on register button

my user details whatever details i have

provided

i should be registered and should be

redirected to the

dashboard page right so this is

something which is

functional aspect now the non-functional

aspect of the same operation would be

when i click on register button

or register link how much time or what

is the response time

to open the registration form right so

if

i am looking for this particular

response time say for example it is

taking you know two seconds

um then if i'm verifying this particular

aspect

the response time when i click on

register link

to open the register registration form

then

this is known as non-functional testing

if i'm interested into

the response time of particular

operation then that is non-functional

aspect

of the testing similarly once i click on

register

button here after filling out all the

details

how much response time it took to

basically redirect me to the

dashboard page so that is the response

time i am verifying so this type of

testing that you do

to verify the response to verify how

stable

application is that is non-functional

testing right so i'll cover

this non-functional testing a lot more

data but this is brief

um you know introduction what exactly

non-functional aspect is

there are many more non-functional

aspect that you'll be verifying in the

non-functional testing

right so responsiveness or response time

is one

factor of it so that is

um the brief now let me

um so the first thing we check is the

responsiveness

so i'll write responsiveness

of the application and then second

is the stability right so when we say

responsiveness

how the application is responding

on a particular condition or the load so

for example

in the festive season e-commerce website

have

lots and lots of load right so there

will be lot of

people who will be buying the items from

amazon from ebay so during the festive

season

there will be thousands and thousands of

users

concurrent users at one particular time

to buy the item or

say for example there is a sale declared

or

there is a sale on a particular you know

day then on that particular day there

will be

a huge amount of users or spike of users

on the website and then

in that particular condition how the

application is responding so when you

are verifying the responsiveness

then that is the non-functional aspect

and that is non-functional testing

whether your

application is stable in those heavy

load condition

if you are verifying the responsiveness

and stability this is

non-functional testing in the

non-functional testing what are

uh some of the you know performance

indicator basically so when you do

non-functional testing you verify

certain things so there are many

performance indicator

but i'll cover the the most common one

so the first one is basically the

response time right

so you verify the response time

so based on say for example 10 000 users

our concurrent users are accessing

uh ebay website at one particular time

how is the response time for the user

that is trying to access at

that particular peak time right so

whether the website is loading within

five

seconds or it is taking you know one

minute

okay so if this is not acceptable if

this is you know

taking a lot of time there will be a lot

of users frustrated and they'll leave

the site and

they won't access it right so this is

what basically the response time is all

about so

when uh you know during a peak load of

time

peak load what is the response time and

normally what is the response time so

if you are verifying the response time

so that is one of the factor in

non-functional testing or the

performance indicator

the second one is the processing time

right so processing

time so when we say processing time how

much time it takes to process say for

example

a customer came to the website and

they added the order they added items in

the order and

submitted the order made the payment so

after making the payment

how much time it took to process that

whole

payment and send the response back to

the customer

so that is the process time or

processing time um

so this is one of the second indicator

that you mostly check into the

non-functional testing or the

performance testing

uh the third one is uh the concurrent

user volume

right so concurrent

user volume okay so concurrent user

volume we've already touched base on it

so

say for example there is a sale going on

there will be thousands and thousands of

content user

trying to buy the on sale items on the

e-commerce website

so you verify the responsiveness and

stability of the application

during you know concurrent user volume

or when there are lots and lots of user

at one particular time so

these are some of the performance

indicator and in the non-functional

testing of performance testing

you basically verify how reliable your

application is how robust it is

so all these are some of the factors you

consider in the non-functional testing

now let me cover what our main type of

non-function testing of performance

testing

that we do so performance testing is one

type of non-function testing

and within performance testing there are

many subtypes right so

uh the main subtypes

will cover in this particular tutorial

and then i'll also cover

those subtypes with example in upcoming

tutorial

right so let me remove this

and the first non-functional testing or

um you know the performance testing i

want to cover is load testing

right so load testing this is very

common

um you would have heard so let me write

all of those so load

and then stress testing so these are the

common types of non-functional testing

or the performance testing that you will

hear

and you need to understand all these in

detail right so that you can explain to

the interview

the third one is soak testing

so soak testing

fourth one that will explain is volume

testing and fifth one

is spike testing

okay now let's start with

load testing so say for example you have

the e-commerce website okay and in this

particular application

your customer has given you the

non-functional requirement

say i want this particular application

to work perfectly fine if

up to 5000 concurrent users right so

five

up to five thousand concurrent users the

response time

for this particular website should be

less than

you know five seconds okay

so in this particular case what

you do in load testing is basically you

verify

that when the 5000 concurrent users are

accessing this particular application

the response time that you are getting

should be less than

five seconds so when there are five

thousand concrete user accessing

the particular website so uh in the

manual scenario what you can

think of is say for example you 5000

people

accessing ebay.com right or any

application that you are trying to build

and when you are the 5000 user

um and you for you the response time

should not be more than five seconds

but in the actual scenario in the real

testing it is not possible to have the

5000 confident physical user trying to

hit

the server it is only possible in the

production so in the testing scenarios

what is done is

the usage of tool is there so with the

tool

uh the 5000 concurrent threads are being

you know created and this um

you know simulates the user's 5000 users

and the response

time is checked whether it is less than

5 second

right so this is what

your load test is all about so testing

the performance of the application on a

particular load that is given by the

user

so if your application is performing or

the response time

is within the accepted limit as provided

by the customer

then your load testing is fine so this

is what load testing

is now when we talk about the stress

test

okay so now load test is verifying that

the response time is within the

expected limit uh when there are 5000 so

for example concurrent users which is

the requirement from the customer

in terms of stress testing what we do is

we verify

the we stress the system

or we increase the number of users and

verify

at which particular point of time the

application will break okay so for

example

uh the requirement is 5000 users and the

response time should be less than five

second

now this is what you will verify in load

test but in stress test what you will do

is you

increase the users to 6000 users and

then say for example once you increase

it to 6000 users

the response time was say 6 seconds

right then you will increase it to 7000

response was eight seconds

so you will keep doing it until the

application

breaks okay so you you just keep making

note of what is the response time and

what is the point when the application

crashes crashes

okay so for example here you have now

increased to

you know 50 000 users concrete users

trying to access the particular website

and the response time is one 1.5

minute okay so this is very high

response time but you keep

increasing the load okay so you keep

increasing the user

and say for example at 5 52 000

users you know the website crash so this

is the point that is basically the

crashing point

and this is what you do in the stress

testing

so in the load testing you verify as per

the customer's requirement the response

time should be within the limit but in

the stress testing you verify

how much load a particular application

is going to handle when you increase the

load

and up to what point the application is

going to

break all right so this is what you do

in the

stress test now coming back

to the soap test

right so in the soak test what you do is

so as we have done in the load test in

the soap test

you run the load test up to

in in the longer duration or up to

extended period of time

right so for example the requirement was

5000 users concurrent users

response time should be less than five

seconds okay

now what you do is uh soap test is

basically

you create five thousand concurrent

users

accessing that particular website and

that test

runs for couple of hours or a couple of

days based on requirement

okay so say for example uh this test

needs to run

for five days okay so

first day and then second third

fourth and fifth okay so you create

the load here of 5000 users

okay and then that

load continues for

five days and you test that the

different

operations with that load for

up to five days when you do that type of

testing it is known as soap testing so

basically you are

uh you know running the test for

extended period of time on the peak load

okay so that is what so testing is all

about

then if we talk about the volume testing

now volume testing is

mostly it's it's relevant for the

testing of the database of the

application

right so here we are more concerned load

stress and so we are concerned about the

users

concurrent users accessing the website

or the portal

but when we talk about the volume

testing it is about the

size of the database or when you

input a lot of data into the database

or you fill the data

completely or reduce the size of the

database

right uh not not reducing the size

basically say for example

your database size is of you know 5gb

and for that 5gb database you fill it up

and then verify how the application

behaves

then that particular you know type of

testing or the non-functional testing is

known as volume testing so this is

important because

say for example you have the e-commerce

website and when you start

getting lots and lots of order your

database or the

or database will fill right so once your

database

is full or near full how the application

behaves or what is the point when the

when the application will crash so that

sort of testing is also important

say for example the the space is not

left the

database is full then how the

application will behave

right so that is the volume testing now

spike testing is another

type of testing uh non-functional

testing what

you do in this pipe testing is uh in the

load testing we have

the load of 5000 users so basically how

we create

the load test is so there's a ramp up

and then as soon as so in the ramp of

phase the number of users or the threads

are increased and up to 5000 users

with the tool and then you know you have

this 5 000 users

you do the test and then you ramp down

right

now in the spike test what happens is

there are sudden spikes of users and

then sudden

you know reduction of the user so what

happens is suddenly there will be

like 5000 users and then there will be

you know like no user

or reduced to the half and then sudden

increase to the user to the 10 000

and then reduction to zero and again so

there is a spike

of users on the application and then

reduction of the users

from the application and then verify how

the application is performing

in that particular scenario so that is

known as pi

testing so these are some of the

non-functional testing there are many

more

non-functional aspects in non-functional

testing but

in terms of interview these are the five

key

uh you know non-functional testing that

should be good enough for you to explain

what exactly non-functional testing is

and

why non-functional testing is required

in any application so non-functional

testing is required to

you know verify the reliability how

robust the application is right so as we

have seen

basically what will be the response time

whether whether the application is

available

on the high load or high volume or if

the database is

full or near full so these are some of

the scenarios that you can explain

in your interview when somebody asks you

about

what is non-functional testing and what

are types of non-functional testing that

are commonly

uh used and you will hear very commonly

in your project

okay so that's all for this tutorial

hope it was helpful

please do share and subscribe and thank

you very much for watching