ISTQB v4.0 Decision Table Testing explanation with examples

Summary

This tutorial delves into decision table testing, a blackbox technique for analyzing and designing tests. It guides viewers through the process of building and simplifying decision tables, understanding conditions and actions, and calculating test coverage. The video also demonstrates how to apply these concepts to practical scenarios and solve ISTQB exam questions, emphasizing the importance of correctly defining conditions and actions to ensure accurate test outcomes.

Takeaways

• 📚 The video is part of an i2b foundation level preparation course on Udemy, focusing on chapter four: test analysis and design, specifically decision table testing within blackbox test techniques.
• 🔍 The script emphasizes the importance of understanding decision table testing for the i2b certification exam, as it is described abstractly in the syllabus without practical examples.
• 📘 Rex Black's book 'Foundations of Software Testing IQ Certification' is recommended for self-study, despite its cost, as it provides valuable insights from one of the exam's authors.
• 🛠 The tutorial walks through the practical application of decision table testing, starting with building a full decision table based on requirements, defining conditions and actions, and then simplifying the table for easier analysis.
• 🔑 The script explains that conditions and actions are critical in decision table testing; incorrect definitions can lead to flawed test outcomes.
• 🔄 The process of simplifying the decision table involves removing impossible combinations and merging columns with identical conditions to streamline the testing process.
• 📉 The coverage of decision table testing is measured by the percentage of exercised columns out of the total visible columns, aiming for 100% coverage with the minimum number of test cases.
• 📝 The tutorial illustrates how to identify impossible or contradictory situations in a decision table, which is a common task in i2b exam questions.
• 📉 The script provides examples of calculating test coverage from a given decision table, showing how to determine which rules are covered by the test cases.
• 🚫 The video advises that if a question on the exam has four or more conditions, it may be best to skip it due to the complexity and time required to answer correctly.
• 📝 The tutorial concludes by highlighting that while decision table testing is complex, exam questions related to it are often simpler since the tables are pre-built, requiring only analysis.

Q & A

What is the main topic of the video?

The main topic of the video is decision table testing, which is a part of blackbox test techniques covered in the i2b foundation level preparation course on Udemy.

Why is it important to understand decision table testing for the i2b foundation level preparation course?

Understanding decision table testing is important because it is a technique used in blackbox testing, and the i2b foundation level preparation course covers this technique in detail to help students prepare for the K3 level questions in the ISTQB exam.

What are the challenges faced when creating a decision table for testing?

The challenges include correctly defining conditions and actions, ensuring that all possible combinations of conditions are covered, and simplifying the table to avoid redundancy and improve test coverage efficiency.

How can one self-study decision table testing?

One can self-study decision table testing by referring to the book 'Foundations of Software Testing IQ Certification' by Rex Black, and by practicing with examples and scenarios similar to those found in ISTQB questions.

What is the significance of simplifying a decision table in testing?

Simplifying a decision table is significant because it helps in reducing the number of test cases needed to achieve 100% test coverage by eliminating impossible combinations and merging columns with the same outcomes.

How does the video script guide viewers in building a decision table?

The video script guides viewers by providing a step-by-step process, starting with defining conditions and actions, determining combinations, marking actions with 'X' for required outcomes, simplifying the table, and finally, deriving test cases from the simplified table.

What is the purpose of analyzing a decision table in ISTQB exam questions?

The purpose of analyzing a decision table in ISTQB exam questions is to verify if the table is built correctly, identify any mistakes or conflicts, and calculate the test coverage to ensure all conditions and actions are adequately tested.

How does the video script help in understanding the application of decision table testing in practice?

The video script helps by providing additional explanations and examples on how to apply the technique in practice, including how to construct and simplify decision tables, and how to derive test cases from them.

What are the steps involved in simplifying a decision table?

The steps involved in simplifying a decision table include deleting columns with impossible combinations of conditions, merging columns where conditions do not affect the outcome, and ensuring that the table covers all feasible combinations for 100% test coverage.

How can one determine the test coverage of a decision table?

One can determine the test coverage of a decision table by counting the number of exercised columns (feasible combinations of conditions) and dividing it by the total number of visible columns, then expressing the result as a percentage.

Why is it recommended to skip questions with four or more conditions on the exam if time is limited?

It is recommended to skip questions with four or more conditions due to the complexity and time-consuming nature of building a decision table from scratch. Answering such questions can take significantly longer than the allotted time for each question on the exam.

Outlines

00:00

📚 Introduction to Decision Table Testing

This paragraph introduces the topic of decision table testing as part of blackbox test techniques within the I2B foundation level preparation course on Udemy. It emphasizes the importance of understanding decision table testing for the K3 level of the ISTQB certification exam. The speaker suggests using Rex Black's book for additional study, noting that while the book is expensive, it may be available through an organization or an older edition could suffice. The paragraph also outlines the steps for applying decision table testing in practice, starting with self-study materials and progressing to building and analyzing decision tables based on requirements.

05:00

🔍 Building and Simplifying Decision Tables

The speaker explains the process of building a decision table, starting with defining conditions and actions based on requirements. They illustrate how to create a full decision table with all possible combinations of conditions and then simplify it by removing impossible combinations and merging columns with identical actions. The paragraph highlights the importance of simplifying the table to reduce the number of test cases needed for 100% test coverage. It also discusses how to determine the correct actions for each combination of conditions and the significance of simplifying the table to make the testing process more efficient.

10:01

📘 Advanced Decision Table Construction

This paragraph delves into the complexities of creating decision tables with more than two conditions, explaining how the number of combinations increases exponentially with each additional condition. The speaker advises that if faced with four or more conditions on an exam question, it may be best to skip it and return to it later. The paragraph also demonstrates how to simplify a decision table by identifying and merging columns with the same outcomes, regardless of certain conditions, ultimately reducing the number of tests required for complete coverage.

15:03

📝 Analyzing Decision Tables for ISTQB Exam

The focus shifts to analyzing pre-built decision tables for the ISTQB exam, rather than constructing them from scratch. The speaker discusses how to identify impossible or contradictory situations within a table based on the requirements. They provide an example from an official ISTQB sample exam, guiding the audience through the process of validating each rule in the table against the given requirements to find an impossible situation described in one of the answer options.

20:05

🔢 Calculating Test Coverage Using Decision Tables

This paragraph explains how to determine the level of test coverage using decision tables. It demonstrates the process of identifying which rules are covered by the test cases and calculating the percentage of coverage achieved. The speaker uses an example from the ISTQB sample exam to show how to analyze the test cases against the rules in the decision table, ultimately determining the test coverage percentage and selecting the correct answer from the provided options.

25:07

🛠️ Complex Decision Table Analysis in ISTQB

The final paragraph addresses a more complex scenario where the decision table provided in an ISTQB exam question is incomplete, and the examinee must reconstruct a full table to identify conflicting conditions. The speaker illustrates how to separate combined conditions into individual columns and expand the table to its full form. They then show how to identify contradictory rules within the table, leading to the correct answer in an exam question. The paragraph concludes by emphasizing the importance of understanding how to create decision tables for both practical work and solving ISTQB exam questions.

Keywords

💡Test Analysis and Design

Test Analysis and Design refers to the process of evaluating and planning tests to ensure the quality of software. In the video, this concept is central to understanding how to apply various testing techniques, including decision table testing, which is a key part of the chapter discussed.

💡Blackbox Test Techniques

Blackbox testing is a method of software testing where the tester checks the functionality of an application without any knowledge of the internal code. The video focuses on decision table testing as a type of blackbox technique, emphasizing its importance in the context of the i2b foundation level preparation course.

💡Decision Table Testing

Decision table testing is a specific blackbox testing technique used to convert complex business rules into a table format for easier analysis and test case generation. The script describes this technique in detail, showing how to build and simplify decision tables to achieve comprehensive test coverage.

💡Foundations of Software Testing

The book 'Foundations of Software Testing' by Rex Black is mentioned as a valuable resource for understanding decision table testing. It is one of the recommended materials for self-study and is authored by one of the exam creators, making its content highly relevant to the video's theme.

💡Conditions and Actions

In the context of decision table testing, 'conditions' are the scenarios or states that can occur, and 'actions' are the responses of the system to those conditions. The script explains how to define these for building a decision table, which is crucial for creating effective test cases.

💡Test Coverage

Test coverage is a measure of how much of the software's functionality is tested by the test cases. The script discusses how to achieve 100% test coverage using decision table testing by ensuring all combinations of conditions are exercised through test cases.

💡Simplification of Decision Tables

Simplification involves reducing the complexity of a decision table by merging columns with identical conditions and actions or removing impossible combinations. The script highlights the importance of this step in making the testing process more efficient and reducing the number of test cases needed.

💡ISTQB

ISTQB stands for International Software Testing Qualifications Board, which is a global organization that certifies software testers. The video script mentions ISTQB in relation to the exam questions and the certification level K3, indicating the relevance of the discussed techniques to professional certification.

💡Equivalence Partitioning

Equivalence partitioning is another blackbox testing technique mentioned in the script, which involves dividing the input of a software system into groups of similar data from which test cases can be derived. It is used as a comparison to decision table testing in terms of complexity and application.

💡BVA

BVA stands for Boundary Value Analysis, a testing technique that focuses on the boundaries of input ranges. The script briefly mentions BVA as part of the broader discussion on blackbox testing techniques, contrasting it with decision table testing.

💡Self-Study

Self-study is the process of learning independently, which the script encourages by providing resources and suggesting ways to apply the theory of decision table testing in practice. The video aims to support viewers in their self-study journey towards mastering software testing techniques.

Highlights

Introduction to Chapter Four on Test Analysis and Design, focusing on decision table testing within blackbox test techniques.

The video is part of the i2b foundation level preparation course on Udemy, with additional study materials provided.

Decision table testing is described abstractly in the syllabus, necessitating this video for practical application guidance.

Recommendation of the book 'Foundations of Software Testing IQ Certification' by Rex Black for in-depth understanding.

Explanation of the importance of correctly defining conditions and actions in decision table testing.

Construction of a full decision table requires defining conditions, actions, and their combinations.

The significance of simplifying decision tables to improve test coverage efficiency.

How to identify and merge columns with identical conditions and actions to streamline decision tables.

Calculating test coverage as the ratio of exercised columns to total visible columns.

The complexity of building decision tables with multiple conditions and the exponential growth of combinations.

Advice on skipping questions with four or more conditions on exams to manage time effectively.

Analyzing pre-built decision tables in exam questions to find errors or calculate coverage.

Using the decision table technique to derive test cases from given conditions and actions.

The process of identifying impossible or contradictory situations in decision tables.

Comparing the complexity of decision table testing to other blackbox techniques like equivalence partitioning and boundary value analysis.

Practical examples of applying the decision table testing technique to ISTQB exam questions.

Strategies for managing time and deciding when to skip complex questions during the ISTQB exam.

Conclusion summarizing the importance of understanding decision table testing for both practical application and exam preparation.

Transcripts

hi everyone today we'll take a closer

look at chapter four test analysis and

design we will learn the section

decision table testing in the topic

blackbox test techniques let's

begin this video is a part of the i2b

foundation level preparation course on

udemy for more information check the

description below the

video we will find out what setting

materials we can use for selfstudy also

together with you we'll find the correct

answers to several iqp questions with

the help of the theory let's begin with

study

materials as with the equivalence

partioning and bva the decision table

testing is described in a syllabus in a

very abstract style without examples and

additional explanations which are

necessary for the questions of the K3

level that is why we created this video

to give you additional explanations on

how to apply the technique in practice

however we will start with

self-studying

Additionally you can WR information

about the decision table testing in the

book foundations of software testing IQ

certification by rex black this is one

of the authors of the exam and his

explanations will be very helpful with

the threat it doesn't matter which

version of the book you find Third

Edition or fourth edition both have

valid

information the problem is that the

books are not freely available as they

are quite expensive but maybe they are

available for your organization or you

might be lucky enough to find at least

the 2011

addition now let's learn how you can use

Theory written in the syllabes in

practice you can pause the video and

familiarize yourself with the content of

the slide we presented the theory of the

syllabus in a logical sequence of

actions that must be done in a simplest

test cases on decision table

testing it is important to note that

using this technique in practice and

answering IP questions are two very

different things at work when you use

the test design technique you will need

one analyze the requirements two

determine conditions and actions three

build a decision table and it is in the

third step that there is a main

difference in I toy questions the

decision table is already built very

often you need to analyze whether it is

built correctly find a mistake in it or

simply calculate the coverage and for

this we still need to know how to build

a decision

table

that is why we will start our tutorial

with the construction of two tables

based on the requirements similar to

those that you can meet in iqb questions

you can pause the video and read the

requirements and try to build a decision

table yourself and then compare the

results at work you can use AI it copes

quite well with such tasks however you

must know how to build tables in order

to be sure that the AI does not make

mistakes and then on exam you will not

have the opportunity to use artificial

intelligence therefore we will go

through all the steps of using decision

table testing to derive test cases the

first step is to build a full decision

table that has enough columns to cover

every combination of

conditions we need to define the

conditions and the resulting actions of

the system these form the rows of the

table usually with the conditions at the

top and the actions at the bottom let's

find the conditions in our requir ments

for beginners this is quite a difficult

task that is why in the eyes to be

questions are built for us in short we

have two conditions this may or may not

be the first attempt at the exam a

candidate may or may not pass the

exam that's how we write in table column

conditions have only two values yes or

no and accordingly we write them in such

style that one condition corresponds to

Boolean values often in the form of

questions

let's check the actions now those are

easier to Define in the requirements and

we can Define three actions Grant access

to practical

exam offer a second try and ban from

attempting for one month this is most

difficult and the most critical point in

the decision table test design technique

if the conditions and actions are

incorrectly defined all subsequent steps

will lead to incorrect

results the next step in building a

complete decision table is determine the

combinations of binary values for the

conditions in reality values are not

always binary sometimes one condition

can have three or more values but this

greatly complicates the construction of

the table therefore in istb questions

the conditions are mostly

binary if we have two conditions Each of

which has two values true or false then

the table will have four possible

combinations true true true false false

true false false

if there were three conditions then

there would be eight combinations if

four then 16 we'll talk about the

formula a little later in this video

let's move on to the next

step in the vast majority of cases the

sign X indicates that the action must

take place if the action cannot take

place then the cells are left

empty the full decision table will look

like

this the first rule is if this is the

first attempt the exam and the exam is

passed successfully then access to the

Practical exam is provided we Mark the

action to provide access to the

Practical exam with an X and we leave

the other two actions

empty the rule does not say anything

about whether it should be the first or

second attempt accordingly the mark acts

on the second combination as well we do

the same with other combinations of

conditions true false false true false

false this is called a full decision

table we have all possible combinations

of conditions we Define actions for each

of the

combination once the complete table is

created we can simplify it and we advise

you to start with the deleting columns

containing invisible combinations of

conditions but in our requirements there

is no mention of any restrictions or

impossible combinations there are only

conditions and

actions with the help of this we can

easily determine which action refers to

which combination of conditions

sometimes there are conflicts in tables

based on conditions for example some

combination would lead to two actions or

two contradictory actions at the same

time but not in our

case accordingly we skip the step and

move to the merging columns in which

some conditions do not affect the

outcome into a single

column for this step you first need to

pay attention to

actions and to find find those rules

where there are the same actions and the

same results in our case these are the

first and third rules as you can see

access to the Practical exam is provided

in both

cases after that we look at the

conditions that is if the theoretical

exam is passed then access to the

Practical exam is

granted that is it does not matter

whether it's the first attempt or not

accordingly instead of true false marks

we can put a

Dash as a result we get two identical

columns which can be merged into one

this is how the table is simplified you

may have the question for what purpose

do we need to simplify the table and the

answer to this question is in the next

step in decision table testing the

coverage items are the columns

containing feasible combinations of

conditions to achieve 100% coverage with

this technique test cases must exercise

all these columns

as you can see after simplifying the

table we have only three columns three

combinations that lead to different

actions accordingly we only need three

tests to achieve 100% test coverage we

write only one test per column per the

rule pass the exam on the first attempt

fail the exam on the first attempt fail

the exam on the second attempt and we do

not need to separately test the scenario

of passing the exam on the second

attempt coverage is measured as the

number of exercise columns divided by

the total number of visible columns and

expressed as a percentage we have three

columns and three rules and we have

three tests Each of which covers one of

the rules accordingly the test coverage

is

100% if we did not simplify the table

then we would have four columns and four

rules accordingly with three tests we

would achieve only 75% coverage the

second column would need an additional

test

pass the exam on the second attempt this

is why the tables are simplified to

cover more conditions and actions with

fewer tests this may not seem important

but let's take another example and let's

complicate the description of the task

with just one

sentence you can pause the video and

read the requirements and try to build a

decision table yourself and then compare

the results we start from scratch like

last time and we start with the full

decision table we need to Define

conditions and actions this time we have

three conditions two exams that can be

passed or

failed as we said this is the most

difficult step because there are many

options for how to build the

table so we defined three conditions

theoretical exam past practical exam

past and the first attempt of the exam

let's define actions

now again there are several options for

defining actions but we will highlight

four issue a driving license request

additional driving license request to

take the exam again ban from attempting

for one month and now we can move on to

the next

step Mark the conditions as yes or no or

true or false or other marks that you

like

better this time we have eight

combinations in total as we said with

each subsequent Boolean value of the

condition we get twice as many

combinations that is we have two states

true and false and we have three

conditions accordingly we have two in

the cube multiply 2 by two and by

two this is important to understand in

order to build complete decision tables

if you have one condition that can be

true or false then you only have two

options true and false since you have

two conditions then you you already have

four options four combinations of true

and

false according to each additional

condition the number of combinations

increases

twice eight if three conditions and 16

if

four accordingly now it becomes clear

why to simplify the

tables after all the more combinations

the bigger and more complicated the

table the authors of istb tests mostly

understand the complexity of of using

the decision table technique and

therefore in most questions you will

find two or three

conditions however there are

exceptions for example aqb has questions

like this where you have seven

conditions yes there are certain

limitations in the description but they

do not simplify the

situation the full table looks like this

it's very difficult to create it and

even worse it's quite easy to make a

mistake

therefore Our advice is as follows if

you are unlucky and there is a question

with four or more conditions on the exam

we advise you to skip it and come back

to it when you answer all the other

questions all questions have the same

value one point and finding the correct

answer to a question with four or more

conditions can take much longer than 5

minutes but mostly it is not the case as

you can see both IB examples have only

three condition conditions in most cases

the tables are built for you and you

only need to analyze them and answer the

question let's go back to our

table long story short we have eight

possible combinations of the states of

conditions let's move on to the next

step we need to label the consequences

of each combination with the X

sign accordingly read the conditions

carefully and Mark each action with an X

when the ction must take place according

to the

conditions the first rule as as follows

if the candidates have successfully

passed both the theoretical and

practical exams the driving license is

issued so we put an x mark on the action

issue a driving

license the rule does not say anything

about whether it should be the first or

second attempt accordingly we mark x on

the second combination as

well and in this way we put all eight

marks this is the most difficult and

longest stage the more rules and

conditions you have described in the

requirements or use a story The more

difficult it is to build a

table let's move on to the next

step now we have to simplify the

complete decision table we start with

deleting columns containing infusible

combinations of conditions this time we

have such

conditions we have this contradictory

requirement only candidates who have

successfully passed the theoretical exam

a granted access to the Practical exam

in fact it can be both an action and a

constraint but for our example we

decided to use it as a

[Music]

constraint the rules from the fours to

the E provide that theoretical exam is

failed after that there is a condition

regarding the Practical exam which is

twice true and twice

false and we can replace these true and

false with na a this means that the

condition is invasible for a given Rule

and when we do this we will get two

identical columns that can be

merged rule five and Rule seven now they

are the same and we can delete one of

them same with rules six and 7even if

the theoretical exam is failed and it

was not the first attempt then the

candidate is banned for one month one of

these columns can be

deleted this is not an ideal example of

delete deltion because there are rules

that would delete all columns in general

but we wanted to show you that there is

no need to rush to delete first you

should Mark The Columns as

na thus we have only six columns left

which significantly reduces the number

of tests required for 100% test coverage

let's move to the next

step merging columns in which some

conditions do not affect the outcome

into a single

column as in the previous example the

first rule and the second rule can be

merged into one regardless of whether it

is the first attempt or not if both

tests are passed then the driver's

license is issued thus we only have five

columns in the table and the last step

remained to achieve 100% coverage with

this technique test cases must exercise

all columns accordingly five tests are

needed to test five

columns as we mentioned earlier the

decision table technique is quite

complex after all the decision table

itself is very difficult and

timeconsuming to

build luckily in most questions the

table is already created and we only

need to analyze

it that's all we discussed all the

theoretical and practical aspects of

applying the decision table testing test

design Technique we hope that it is now

clear to you and it will be easier to

answer IB questions and also to use it

in

practice let's try to use what we have

learned about the decision table test

technique in the example of questions

from the official IB exam

sampol there is 100% chance of having

one question of K3 level on the exam

ticket related to the decision table

testing the K3 level questions are the

most difficult some you can answer in 1

three minutes but some questions are so

twisted and confusing that you can spend

10 or more minutes minutes on

them in the new sample exam version 4.0

document we can find the following

question those who want to try to answer

the question themselves can pause the

video let's find the answer to it in the

study

materials in previous questions about

blackbox test design techniques

equivalence partitioning and bva we

started with test by reading the

description of the question very

carefully to find the information that

can make changes to the existing

checklist

the situation is different with a

decision table testing Technique we

don't need to create a decision table we

need to analyze the existing one and

find the right

answer that's why in most questions we

either do not follow the checklist at

all or use only one or two steps from

the

checklist as we said before creating a

table based on requirements is quite a

long and complex task where it is very

easy to make mistakes that is why why in

I to QB questions the tables are

generated for

us this greatly simplifies the search

for correct answers to questions for

example this question should based only

on the feature description of the

customer relations management system

find rules that describe an impossible

situation let's try to do

it we have four answer options and we

have to check whether the rule in the

table meets the conditions in the

requirements for this

we needed experience in building tables

on our

own the first rule is anyone can rent a

bicycle but members receive a 20%

discount as we see the condition of

being a member is set to a true and the

action 20% discount is marked as such

was happened with a cross

mark accordingly these table rows me the

conditions in the requirements let's

check the next

condition the second rule is

however if the return deadline is missed

the discount is no longer available as

we see the condition of missed deadline

is set to a false and the action 20%

discount is marked as such what happened

with a

Crossmark accordingly these table rows

also meet the

requirements let's check the next

condition the third rule is after 15

rentals members get a gift a t-shirt as

we see the condition of the 15 rental is

set to a true and the action gift

t-shirt is marked as such was happened

with a cross mark accordingly these

table rows also meet the

requirements thus the fourth rule in the

description table is valid and describes

the possible variance of situations

correctly we will not consider each

answer option and each role in the table

in detail with the same steps we can

determine that answer option B describes

a possible

situation same as answer option C with a

six rule the terms and conditions are

valid and meet the

requirements The Impossible situation is

described only in answer option D as we

see the condition of being a member is

set to a false just like in the previous

rules but there is one difference rules

five 6 and seven

the action gift t-shirt is left blank

the action hasn't

happened but in the rule eight the

action gift t-shirt is marked as such

what happened with a cross

mark since the third in the requirements

is described as that after 15 rentals

members get a gift a t-shirt this means

that only members receive a

t-shirt accordingly answer option D

describes an impossible situation

after 15 rentals not a member got a gift

a T-shirt and is the correct

answer all other options a B and C are

valid and describe possible

situations as you can see in this

example we did not need to follow the

checklist because the description table

was built for us and it was only

necessary to analyze its validity let's

check one more example of the I top

question in the new sample exam version

4.0 document we can find the following

question those who want to try to answer

the question themselves can pause the

video let's find the answer to it in the

study

materials as we can see the question is

similar to the previous one sometimes

the table is already created for us and

we need to determine the level of test

coverage accordingly we cross out two

main steps from our checklist and we

leave only the last step in decision

table testing the coverage items are the

columns containing feasible combinations

of conditions to achieve 100% coverage

with this technique test cases must

exercise all these

columns so we start with the first test

the first condition is cheral equals to

125 which aligns with two rules rule

three and four are both rules that

require a cholesterol level of 125 to

200 we Mark rule three and four against

the first test and must now look at the

next condition blood pressure equals to

141 as you can see the third rule

involves a blood pressure of less than

140 accordingly the first test case

covers only the force Rule and thus we

need to consider four more test

cases again as in the previous question

we will not explain each test case step

by step because it's quite

obvious just note that first two tests

cover rule four the third and fourth

test cover rule two the fifth test

covers the fifth Rule now that all test

cases have been analyzed we already did

this at the beginning of the

tutorial it is best to illustrate this

with the help of a table as you can see

we have a lot of rules the first and

third rules are not covered by the tests

the second rule is covered twice by the

fact that we have two tests for one rule

does not affect the final coverage it

doesn't matter how many tests per rule

it only matters if the rule is covered

by the tests or

not there are five rules in total and

only three of them are covered by tests

one rule is

20% accordingly the test coverage will

be

60% and this is answer option b as you

can see although decision table testing

is a more complex technique than

equivalence partioning and bva the

questions on it are simpler provided

that you do not need to build a complete

table of conditions and actions let's

check another example of an IB

question in the new sample example

version 4.0 document we can find the

following

question those who want to try to answer

the question themselves can pause the

video this question which at glance

asmol is actually much more complicated

than the previous one after all we have

a shortened table of conditions and

actions and we need to build a full

table that was before the

reduction from our checklist we only

need one item marging columns in which

some conditions do not affect the

outcome into a single

column so we have a table in which there

are three dashes we need to separate the

combined columns into separate ones

instead of a dash we can write true or

false thanks to this it will be easier

to illustrate how a complete table of

conditions and actions is

formed in this way two columns are

formed from the First Column one of

which must have the condition first

attempt at the

exam true and the other column will have

it as false accordingly the First Column

is cleared and we can proceed to rule

four dividing it according to the same

steps

and thus instead of three columns and

three rules we got five the next rule is

complicated as you can see two

conditions are combined into one the

condition first attempt at the exam is

marked with a dash and the condition

practical exam passed is marked with a

dash and here it is important not to

make a mistake and disconnect both

conditions in a

row first let's separate the first

condition in the same way as before as a

result we will get two new columns one

is marked as true the other as

false and as you can see as a result of

that unmar we got two more columns with

a dash accordingly we will get two

additional

columns first let's note that both can

have a third condition practical exam

passed both true and

false in this way we will get eight

columns instead of three that we had the

beginning as we said this question is

much more complicated than it seemed at

first

glance the last step is to search for

conflicting conditions and it doesn't

take long to find them the sixth rule

has all the conditions as false and the

corresponding action requests to take

the exam again the eight rule also has

all three conditions as false but a

completely different action request

additional driving

license

thus answer option D is correct the

false false false conditions will show

that there are contradictory rules in

the decision

table even this difficult question in

our opinion is much simpler than the

equivalence partitioning and bva because

it has much less ambiguities and

contradictions it is almost never

necessary to build a decision table from

scratch in eyes to K questions

accordingly we rarely go through all the

steps in our checklist still it's very

important to know exactly how to create

a decision table because at work you

will have to create them

yourself also without understanding

exactly how to create a decision table

it will be almost impossible to solve

the questions of

istqb for the topic blackbox test

techniques we have about 50 questions in

total about 10 of them will be related

to the section decision table testing if

is more than enough for

practice well that's the end of today's

tutorial we hope to see you in the next

lecture