ISTQB FOUNDATION 4.0 | Tutorial 37 | Error Guessing | Experience-Based Techniques Techniques | CTFL

Summary

This tutorial delves into experience-based test techniques, emphasizing their reliance on the tester's intuition and past experiences. It highlights the importance of domain knowledge and understanding typical defects in product testing. The video introduces error guessing as a technique, which complements formal methods by targeting areas prone to defects based on tester's experience. Error guessing, or fault attack, is presented as a valuable approach, especially when formal techniques fall short, such as in poorly defined specifications, time pressure, or with teams lacking formal training. The tutorial encourages testers to use their expertise to uncover potential defects, thereby enhancing test coverage and confidence.

Takeaways

• 📘 Experience-based test techniques are driven by the tester's past experience, domain knowledge, and understanding of typical defects found in similar products.
• 🔍 These techniques are informal and rely on the tester's intuition and judgment rather than formal methods or calculations.
• 🚫 Freshers or those without relevant domain experience should not apply experience-based techniques as they lack the necessary background.
• 🛠 Experience-based techniques are secondary approaches and should be used when formal techniques are not applicable.
• 💡 They are particularly useful in scenarios where formal techniques cannot be applied, such as poorly defined specifications, time pressure, or when the testing team lacks formal training.
• 🎯 Error guessing is an experience-based technique where testers use their intuition to identify potential defects based on past experiences and knowledge of common issues.
• 🚀 Error guessing can be conducted as a 'fault attack', a systematic approach where the tester actively seeks out specific types of defects they expect to find.
• 📝 Writing detailed test cases for error guessing is not necessary; high-level outlines or direct interaction with the system can suffice.
• 🤔 Whether a defect is found or not, error guessing provides a win-win situation by either uncovering issues or increasing confidence in the system's functionality.
• 📈 The results of error guessing can be summarized at a high level, evaluating the value added to the overall testing process and the effectiveness of the technique.
• 🌟 The success of experience-based techniques, including error guessing, hinges on the tester's ability to draw from past experiences and apply that knowledge to new testing scenarios.

Q & A

What is the main focus of chapter 4.4 in the tutorial?

Chapter 4.4 focuses on experience-based test techniques, specifically starting with the first technique, error guessing.

What are experience-based test techniques driven by?

Experience-based test techniques are driven by the tester's past experience in testing similar products, domain knowledge, and knowledge of typical defects.

Why are experience-based test techniques not suitable for a fresher or someone switching domains?

Experience-based techniques are not suitable for a fresher or someone switching domains because they require past experience, domain knowledge, and an understanding of typical defects within a specific industry, which they may not possess.

What are the scenarios where experience-based test techniques are the only options to be applied?

Experience-based test techniques are the only options when specifications are poorly defined, there is time pressure, or the testing team is not formally trained on testing fundamentals.

What is the difference between formal and experience-based test techniques in terms of justification and coverage?

Formal techniques are well-documented and defined, making it easier to justify coverage and determine scope. Experience-based techniques are driven by the tester and may not always be justifiable or have clear coverage measures.

Why should experience-based test techniques be seen as a secondary approach?

Experience-based techniques should be secondary because formal techniques are more structured and easier to justify. They should only be used when formal techniques are not applicable.

What is the concept of error guessing in testing?

Error guessing involves the tester using their intuition and past experience to identify potential defects in the system that may not have been caught by formal testing techniques.

What is the term used for the systematic approach of conducting error guessing?

The systematic approach of conducting error guessing is called fault attack.

What is the win-win situation of error guessing in testing?

The win-win situation of error guessing is that if a defect is found, the tester's intuition is validated. If no defect is found, the tester gains increased confidence in the system's functionality.

How can the results of error guessing execution be documented?

The results of error guessing execution can be documented in a high-level summarized way, noting what was done during the execution and how it added value to the overall testing results.

What is the basis for the error guessing technique?

The error guessing technique is based on the tester's intuitions and guesses, informed by past experience with how the application has worked, common developer mistakes, and failures in other applications.

Outlines

00:00

😀 Introduction to Experience-Based Test Techniques

This paragraph introduces the concept of experience-based test techniques, emphasizing their reliance on the tester's past experience, domain knowledge, and understanding of typical defects. It clarifies that these techniques are not formalized and are best suited for testers with significant experience in similar applications or domains. The paragraph also discusses the limitations of these techniques, especially for those new to testing or switching domains, and highlights the importance of formal test techniques as the primary approach, with experience-based techniques serving as a secondary option when formal methods are not applicable.

05:02

🕵️‍♂️ Error Guessing: An Experience-Driven Testing Approach

This paragraph delves into the specifics of error guessing, a technique within the experience-based category. It outlines scenarios where formal testing methods may not be feasible, such as poorly defined specifications, time pressure, or a lack of formal training in testing fundamentals. The paragraph explains that error guessing involves the tester's intuition to identify potential defects based on past experiences and knowledge of common issues in similar applications. It also introduces the term 'fault attack' to describe a systematic approach to error guessing, where the tester has a predefined idea of the defects they are looking for and actively seeks to uncover them.

10:04

🎯 The Value of Error Guessing in Testing

The final paragraph wraps up the tutorial by discussing the value of error guessing in a testing context. It suggests that this technique is based on the tester's intuition and past experiences with how applications have performed and the types of errors developers commonly make. The paragraph emphasizes that error guessing can be a win-win situation, as it either uncovers defects or increases confidence in the application's functionality. It concludes by encouraging continuous learning and exploration in the field of testing.

Keywords

💡ISTQB

ISTQB stands for the International Software Testing Qualifications Board, which is a non-profit organization that certifies the competence of software testers. In the script, the video is a tutorial for the ISTQB Foundation Level certification, indicating the educational context of the content.

💡Test Analysis and Design

Test Analysis and Design is a phase in the software testing process where testers evaluate the software requirements and design test cases. The script discusses this as part of Chapter 4, emphasizing its importance in the certification material.

💡Experience-based Test Techniques

These are testing methods that rely on the tester's experience, intuition, and knowledge of similar applications and technologies. The script explains that these techniques are used when formal techniques are not applicable or to add more value to the testing process.

💡Error Guessing

Error Guessing is an experience-based test technique where the tester uses their intuition to identify potential defects in the software. The script describes this as a method of directly targeting areas believed to be prone to errors based on past experiences.

💡Domain Knowledge

Domain Knowledge refers to the understanding of the specific industry or area in which the software operates, such as banking, e-commerce, or healthcare. The script mentions it as a critical component of a tester's experience that influences the effectiveness of experience-based test techniques.

💡Formal Techniques

Formal Techniques are structured and well-documented testing methods, such as black box and white box testing. The script contrasts these with experience-based techniques, noting that formal techniques are more easily justified and scoped.

💡Fault Attack

Fault Attack is a systematic approach to error guessing, where the tester purposefully targets areas of the software they believe may contain defects. The script introduces this term to describe a strategic method of applying experience-based techniques.

💡Freshers

In the context of the script, 'freshers' refers to individuals new to the field of software testing, who may not have the necessary experience or domain knowledge to effectively apply experience-based test techniques.

💡Time Pressure

Time Pressure is a scenario mentioned in the script where there is limited time to complete testing activities. In such cases, experience-based test techniques may be used as a faster alternative to formal test cases.

💡Poorly Defined Specifications

Poorly Defined Specifications are requirements that are not clearly stated or are too high-level, making it difficult to apply formal testing techniques. The script cites this as a situation where experience-based test techniques become the primary option.

💡Testing Fundamentals

Testing Fundamentals refer to the basic principles and practices of software testing. The script discusses a scenario where a lack of formal training in these fundamentals leads to the reliance on experience-based test techniques.

Highlights

Introduction to experience-based test techniques in chapter 4.4 of the ISTQB Foundation Level certification tutorial.

Explanation of experience-based test techniques being driven by the tester's past experience, domain knowledge, and typical defect knowledge.

Distinction between experience-based and formal test techniques, emphasizing the lack of formal approaches in the former.

Discussion on the feasibility of using experience-based techniques for freshers and those without relevant domain knowledge.

Importance of formal test techniques and the conditions under which experience-based techniques should be considered as a secondary approach.

Scenarios where experience-based test techniques are the only option, such as poorly defined specifications or time pressure.

The concept of error guessing as an experience-based technique, relying on the tester's intuition and past experience to identify potential defects.

Error guessing as a win-win situation, providing increased confidence whether defects are found or not.

The systematic approach of error guessing known as 'fault attack', where the tester has a specific defect in mind.

The value of error guessing in identifying special tests that formal techniques might not capture.

The optional nature of writing test cases for experience-based techniques, allowing for high-level outlines or direct system interaction.

The role of domain experts in applying experience-based techniques despite a lack of formal testing training.

The importance of updating and evaluating the results of experience-based test executions to assess their value.

The reliance of error guessing on the application's past performance, developer tendencies, and failures in other applications.

Encouragement for continuous learning and exploration in the context of software testing.

Invitation for viewers to comment with questions and engage with the tutorial content.

Transcripts

Hello friends and greetings for the day

welcome back to another tutorial on istd

KV Foundation level certification we are

in chapter 4 talking about test analysis

and design and today we will be stepping

into the next segment that is 4.4

experience-based test techniques and as

a part of this tutorial today we are

talking about the first technique in

this category that is error

guessing

before we start talking about the

technique error guessing let's have

let's have quick discussion on this

category once again a little Deep dive

however we have covered this

introduction already as a part of the

4.1 where we were discussing on the

categories of different uh techniques

and uh the same thing we'll be just

elaborating once again here to make sure

that you have a good understanding of it

so a quick discussion on experience

based as I told you experience-based

test techniques are completely driven by

by the experience of the tester which

includes the past experience of testing

similar products at the same time what

domain knowledge the tester process the

domain knowledge here means the type of

the product where it belongs like is it

a banking product is it a e-commerce is

it a healthcare product and so on like

Automotive Etc so domain knowledge is

equally important to add to the overall

experience and third important thing is

the typical knowledge of the defects

given that a person possess the

knowledge of of what kind of defects do

we find in the product it would be very

useful for that person to design the

test cases accordingly and hit only

those particular areas where we quite

often find the defect so most important

thing to highlight here that this

category consists of techniques where it

is completely driven by the tester and

which is best known to the tester so no

formal approaches no formal techniques

are being applied here no calculations

is completely dependent on the tester

who is testing it so the question comes

quite often that hey if a fresher is

trying to perform this uh technique is

that something feasible to say it is

experience-based test technique answer

is not that is a fresher does not

possess any past experience domain

knowledge to certain extent they know

about what is the industry but they

literally do not have the domain

knowledge and they do not have any

knowledge of typical defects another

example could be that if you say if I

have worked in banking industry as a

test manager for 7 years and now I'm

switching to Automotive is that like I

can use experience-based test techniques

answer is absolutely not again because

this person is certainly experienced but

in a different domain and different

industry and has tested different type

of product in past whereas what this

person is trying to do now is completely

irrelevant or different than what he or

she was doing in the past so that's

again something those scenarios where we

cannot call it as experience-based test

techniques or these type of people

cannot apply these category techniques

so let's quickly check what we have to

say from the syllabus outline number one

experience-based test techniques

basically uses tester skills intuitions

and experience of similar application

and Technologies these techniques are

useful in identifying the special tests

which are not easily captured by the

formal techniques now let me tell you

something more important here that is

when it comes to the formal techniques

which is more of like black box and

white box they are very well documented

and well defined so it's very easy to

justify the coverage measured or at the

same time is easy to determine what you

are actually testing and whether it is

in the scope or not when it comes to

experience-based test techniques it will

be completely driven by the tester and

dependent on them so we may not be able

to sometime justify that how did you

really cover every single thing so we

most mostly we Define and you know

understand that we should always make

use of the formal test techniques as

much as possible

until unless the formal test techniques

are not applicable we must not look

forward to experience based so

experience based test technique should

be always seen as a secondary approach

if formal techniques are not applicable

however in some of the cases formal

techniques can be conducted and on top

of it a round of informal technique

which is experience-based test

techniques can always add more value

better coverage and more confidence so

formally executing some test

and then a roundoff experience-based

test technique can be a really good

method also to add here these techniques

are usually applied after applying

formal techniques and there are a few

scenarios where these are the only

options to be applied now that's the

most important thing to highlight at

this point of time that is that there

are certain cases where formal

techniques are not at all applicable and

you only have the hope of the

experience-based test techniques and

what are they number one specification

are poorly defined now when I say

specifications are poorly defined it

simply means that the requirements are

not clearly mentioned or requirements

are very high level and given that

requirements are very high level I

cannot apply blackbox test techniques

and in that context I may be a tester so

I don't even know what is code so I

cannot go with white box so in this case

only experience-based test technique

will be applicable the second scenario

here is time pressure so of course

sometimes in a project at the end of the

day you may undergo a time pressure

which means you're remaining with more

activities more executions to be

performed but you have limited timeline

available or deadline is very close in

that context running formally written

test cases would be very timec consuming

so you keep your written test cases

aside and start using your experience to

run the test in order to cover the

remaining part of the system however

that's not something we should be used

as a primary approach this is only in

the worst situations third where we say

that the testing team is not formally

trained on testing fundamentals and

that's another interesting fact so there

might be domain experts who are working

in different Industries uh for example

if you go to an automotive Factory that

is Workshop you can find people working

and assembling cars for 20 years 25

years and so on if they if you ask them

hey can I have a look on your test cases

they would say we don't know what is

test cases but the question is they have

been testing cars for last 25 years so

they really have good experience and

domain knowledge and they are able to

assemble the car in a way that it

functions well so it does not really

mean that they know what is equence

partition what is boundary value

analysis but still they are testing the

system so yes in this case also when the

team is not formally trained on testing

that means they don't know what are the

test techniques they can they will be

certainly using experience-based test

techniques as their primary approach so

let's quickly look at the very first

technique which which is error guessing

as a part of this tutorial and try to

understand how this technique is

different from the formal technique so

the concept of error guessing goes

something like this say assume that you

have applied some of the formal

techniques like white equence partition

boundary value analysis Etc and you got

some test 10 10 test cases you executed

them you got some output XYZ and now you

thinking that you are some somehow

underc confident or you think that

probably there are more defects which

might be underlying and we don't want to

take a chance

then you guess or Intuit the errors

which you may have in the system and

that certainly depends on your past

experience the knowledge of the demand

and the topics the difficult defects

what you may have P faced as part of the

past experience or testing so certainly

it is completely dependent on the

intuition of the individual that what

they think could be probably wrong in

the system and you directly go and hit

them all the experience-based test

techniques are not necessarily

recommended to have a written test case

so you can write not predefined test

cases like high level onliners and that

would be enough to execute the test

however that's optional so if you wish

to write uh test cases on High level you

can do that but even if you don't write

that's absolutely fine so you can just

go and interact with the system directly

without any kind of documentation and

execute your test cases to find the

defect let me tell you error guessing is

what the name is of course as the

approach what we discussed but certainly

comes with win-win situation in both the

scenarios whether you get a def or not

so if you get a def you certainly were

right in your intuition and even if you

don't get a defect you are still happy

that you tried it but it's working fine

so I'm at least having a level up on the

confidence so such techniques which is

like experience-based techniques

certainly add win-win situations from

both the cases even if you get a def or

you don't get a defect also to add here

this systematic approach of conducting

error guessing is called as fault attack

purposefully there is a name for this

approach being executed called as fault

attack the reason is here you know what

defect are you looking for that means

your strategy your execution is

dependent on the type of defect which

you already know but in generic testing

we say the objective is finding defects

right we don't know what we are looking

for we are testing the functionality and

during that we find something which we

don't expect but here we know what we

are expecting what we are looking for

all we know that is there's something

like this which quite often happens and

I'm just trying to uncover that so

that's the reason the approach of

executing error guessing is specifically

called as fault attack so how as far as

you remember these terminologies you

will be able to answer a question also

to add further the same story what I

told you earlier that is updating the

results of execution and evaluating

further needs to the test of their

executions can be done in a very very

high level that means a very high level

summarized way of uh result can be

created in terms of what have you done

during the execution and does that

really added value or how did that add

the value to the overall results and

plus the situations what we make use of

of course the error guessing is based on

how the application has worked in the

past what type of mistakes the

developers tend to make and failures

that have occurred in other applications

so put together this technique is

completely based on your intuitions and

guesses based of based on your past

experience and you try to execute the

system as much as possible to see if you

can find some defs so that's all from

this particular tutorial team should you

have anything else feel free to comment

below I'm always there to address your

quties and answer them well till then

keep learning keep exploring keep

understanding the context thanks for

watching the video team and happy

learning

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