Software Testing Tutorial #19 - What is White Box Testing

Summary

This tutorial explains white box testing, highlighting its differences from black box testing. Unlike black box testing, where the internal code isn't visible, white box testing focuses on the internal structure and code logic of the application. The video provides examples, such as a calculator application, to demonstrate how testing methods like statement coverage, branch coverage, condition coverage, loop testing, and path testing are applied. The tutorial emphasizes that white box testing is typically performed during unit and integration testing phases, with tools like JUnit used for verifying code coverage.

Takeaways

• 🧐 White box testing involves understanding the internal structure of the code, unlike black box testing where you only verify input and output.
• 💻 In white box testing, the tester has knowledge of the internal workings, such as methods and classes used in the functionality.
• 🔍 White box testing is also known as clear box, glass box, or structural testing, as it focuses on the internal code structure.
• 🧑‍💻 An example of white box testing is knowing the code behind a calculator, such as how addition or multiplication functions are implemented.
• 📑 Techniques in white box testing include statement coverage, branch coverage, condition coverage, loop testing, and path testing.
• ⚙️ White box testing is often used during unit testing and integration testing phases to ensure code-level functionality.
• 📊 Code coverage tools are used in white box testing to measure how much of the code has been exercised by test cases.
• 🔗 Developers usually perform white box testing by writing unit tests to cover different conditions and code paths.
• 🔧 White box testing involves verifying how the code handles various scenarios, including valid, invalid, and edge case inputs.
• 📚 Black box testing focuses on input-output verification without any knowledge of the internal code, while white box testing involves inspecting the code itself.

Q & A

What is white box testing?

White box testing is a testing method where the internal structure, code, and implementation of the software are known to the tester. It involves verifying the internal workings of the code, such as methods, classes, and logic flow.

How does white box testing differ from black box testing?

In black box testing, the tester does not have access to the internal workings of the software and focuses only on the inputs and outputs. In contrast, white box testing involves understanding and testing the internal code and structure of the application.

Can you give an example of black box testing?

An example of black box testing is testing a user registration feature on an e-commerce website. The tester clicks the register button (input) and checks if the registration page is displayed correctly (output), without needing to know the internal code.

What are some common types of white box testing?

Some common types of white box testing include statement coverage, branch coverage, condition coverage, loop testing, and path testing. These techniques ensure that all parts of the code are tested for correctness.

What is statement coverage in white box testing?

Statement coverage ensures that every statement in the code has been executed and tested at least once during the testing process.

What is branch coverage in white box testing?

Branch coverage checks that all possible branches of decision points (e.g., if-else conditions) are tested to ensure each branch executes as expected.

At what stages of testing is white box testing typically performed?

White box testing is typically performed during unit testing and integration testing. In unit testing, small units of code are tested individually, while in integration testing, the interaction between different units is tested.

What tools are commonly used for white box testing?

Tools such as JUnit for Java and other unit testing frameworks are commonly used for white box testing. These tools help in verifying code coverage, ensuring the different parts of the code are tested adequately.

How is white box testing applied to a calculator application?

In a calculator application, white box testing would involve inspecting and testing the internal code for operations like addition, subtraction, multiplication, and division. The tester would verify how the code handles valid and invalid inputs.

What is loop testing in white box testing?

Loop testing involves verifying that loops within the code function correctly under different conditions, such as with no iterations, a single iteration, or multiple iterations.

Outlines

00:00

🔍 Introduction to White Box Testing

This paragraph introduces white box testing, explaining the contrast between white box and black box testing. The speaker reviews black box testing, where the tester only provides input and verifies the output without knowing how the internal functionality works, using an example of a user registration process. White box testing is then introduced as a method that focuses on understanding the internal code and functionality, such as the methods and classes used for a given feature.

05:02

💻 White Box Testing and Code Access

The paragraph provides an example of white box testing using a calculator. The focus is on accessing the actual code to understand how operations like addition, subtraction, and other functions are implemented. A simple pseudo-code for addition is used to illustrate how white box testing involves testing code behavior with different types of inputs, such as valid and invalid values. The idea is to ensure the code functions correctly and handles edge cases, like invalid data inputs.

10:02

🧪 Techniques in White Box Testing

This section covers specific techniques used in white box testing, including statement coverage, branch coverage, condition coverage, loop testing, and path testing. These techniques ensure that all parts of the code are covered and tested. Various code coverage tools can help in this process, and the white box testing is generally done during unit and integration testing phases.

Keywords

💡White Box Testing

White box testing is a software testing technique where the tester has access to the internal workings of the system, such as the code, methods, and logic. In the video, it is described as a method of testing where the tester verifies the structure and flow of the code, ensuring that all statements and paths are covered. An example given is testing a calculator’s internal code for addition, subtraction, etc.

💡Black Box Testing

Black box testing is a technique where the tester does not have access to the internal code or structure of the system and only tests the functionality by providing inputs and checking outputs. In the video, it is explained that black box testing focuses on verifying outcomes without knowing the internal code. An example given is clicking the 'register' button on an e-commerce site and checking if the registration page appears without understanding the backend processes.

💡Statement Coverage

Statement coverage is a white box testing technique where the goal is to execute all the statements in the code at least once. In the video, statement coverage is presented as one of the methods of ensuring that every line of code is tested. The goal is to make sure no part of the code goes untested during the verification process.

💡Branch Coverage

Branch coverage is another white box testing method that checks whether each branch (e.g., the 'if' and 'else' statements) has been executed during testing. In the video, this is introduced as a technique to ensure that both the true and false branches of conditional statements are tested to avoid missing any logic.

💡Condition Coverage

Condition coverage focuses on testing all the possible conditions in the code, ensuring that every condition in a decision statement is tested. This helps guarantee that the software behaves correctly under various conditions. In the video, condition coverage is mentioned as part of the comprehensive testing done in white box techniques.

💡Loop Testing

Loop testing is a white box testing technique used to validate that loops within the code work as expected. This includes testing loops with zero iterations, one iteration, or multiple iterations to ensure the program handles different scenarios. In the video, loop testing is mentioned as part of verifying that all loops in the program are functioning properly.

💡Unit Testing

Unit testing is a testing method where individual components or units of a program are tested in isolation. In white box testing, unit tests are typically written by developers to test the code’s internal logic. In the video, unit testing is highlighted as a phase where white box testing commonly occurs, focusing on testing small code segments.

💡Integration Testing

Integration testing is the process of testing how different units or modules of the program work together. In white box testing, this might involve verifying how well different pieces of code interact. The video explains that integration testing is often a stage where white box testing is applied to ensure that combined units function correctly after integration.

💡Code Coverage Tools

Code coverage tools are software tools that help measure how much of the code is covered by test cases. They ensure that all parts of the code are tested during white box testing. In the video, tools like JUnit for Java are mentioned as examples of frameworks that assist in achieving code coverage during unit testing.

💡E-commerce Example

The e-commerce example is used in the video to illustrate both black box and white box testing. In black box testing, the tester checks if the registration page loads correctly after clicking the register button. In white box testing, the tester would examine the code to understand which methods and functions are called after clicking the button, ensuring proper internal functionality.

Highlights

Introduction to white box testing and distinction from black box testing.

In black box testing, the tester has no access to the code and verifies functionality only based on input and output.

White box testing requires understanding of internal code structure, methods, and classes involved in a functionality.

White box testing is also referred to as clear box or structural testing.

Example of black box testing with an e-commerce user registration: testing by clicking buttons and verifying the expected outcomes.

In white box testing, the tester is concerned with the internal operations, such as methods or classes triggered after actions.

Example of white box testing using a calculator, focusing on how the code handles operations like addition and multiplication.

In white box testing, testers can examine code for addition, subtraction, multiplication, and division, checking its behavior with different inputs (valid/invalid).

White box testing includes techniques such as statement coverage, branch coverage, condition coverage, loop testing, and path testing.

Statement coverage ensures that all statements in the code are executed at least once by the test cases.

Branch coverage focuses on ensuring that every possible branch of a decision point in the code is tested.

Condition coverage ensures that each logical condition in a decision statement has been tested with true and false outcomes.

Loop testing verifies that loops within the code are executed properly, including boundary conditions and multiple iterations.

White box testing is typically done during unit testing and integration testing phases, often by developers.

Unit testing frameworks like JUnit are commonly used for white box testing to check code functionality at a granular level.

Transcripts

hello everyone welcome again in the

software testing tutorial

we are going to learn what is white box

testing

so we have already understood about the

black box testing now let us understand

what is white box testing because we

need to understand the difference

between white box and black box testing

so in this tutorial i'll explain

details about the white box testing so

that you know what

white box testing is and then the next

tutorial i'll complete

i'll complete the differences between

black box

and white box testing okay so as we have

understood about the black box testing

so

in the black box testing we didn't had

any access to the code or the

functionality that has been developed

right so this

say for example i'm testing any

functionality

uh i simply will provide the input

and based on the input i'll expect

certain output so

here i'll verify the output

right so if this is the case wherein i

don't have any knowledge of the internal

working of that functionality say for

example

user registration in the e-commerce

website when user clicks on register

after click on clicking on register

i only see the registration page being

displayed

for me right so when i click on register

that click is my input and when

the registration page is displayed with

all the fields that's my output right

so if i'm doing the black box testing

i'll click on register and

i'll verify that the registration page

is opening successfully or not

right so this is black box testing for

me now when we talk about

white box testing white box testing is

concerned about what actually happens

within this box right or

what happens in the actual code so say

for example if i click on register link

i need to have understanding of what

all happens within the code

which is being written for that

particular functionality right so

before this registration page is being

displayed

what all methods are being called what

all classes are being written so

depending on which programming language

you choose what implementation has been

done by the developer

if i am concerned about the details of

those

implementation then that is known as

white box

testing white box testing is also known

as class

box testing clear uh box testing

or structural testing right so uh when

you check

the structure of the code so it's in in

the structural testing there are many

types of

white box testing which will cover in

detail in upcoming tutorials

but as of now just understand when you

are the

when you want to understand the internal

working how the code how the methods are

written

which methods or which class calls which

class so all that details

uh when you are trying to test then that

is known as white box testing now let me

take an example of

white box testing and i'll explain you

know how

you can explain the white box testing to

the interviewer

now say for example i'll take very

simple example of calculator

okay say for example there is a website

all right

and uh on the website you have the

calculator

so usually what you'll do is you have

certain you know like numbers there

so you have the screen and you have

if you are accessing the the calculator

on the website so there will be the

sunscreen and

there will be you know like certain

numbers one two three uh

four five six seven eight nine right

and then plus minus uh multiplication

and division

and equal to sign so very simple so for

example i have taken the calculator

so if you are trying to test the

calculator

using the black box technique what you

will do is uh if you want to you know

test all the functionality you will test

the addition subtraction multiplication

and division right so this is simple

calculators what i'll do is i'll try a

couple of scenarios with the addition so

i'll say

seven i'll press seven and then plus

eight and then i'll verify

uh press equal to and verify that the

sum is what i

expect okay similarly if i want to

verify the subtraction multiplication

division i'll follow

the different scenarios or the test

cases to verify those scenarios

so this type of testing will be the

black box testing for me because

once i press seven and then plus press

plus and then press eight and equal to i

am not

concerned how internally that

calculation

is happening okay so

the internal working of this particular

calculator i don't know

and that is why this is black box for me

when i talk about the white box testing

the same calculator basically what i'll

do is

um i'll open the box right so

as it says white box in black box so in

the white box the box is open or it's

not a black

box for me uh i know

the internal working or i need to know

how the actual calculation happens so in

the white box testing you will

mostly work with the actual code right

so in that particular case what you will

do is

say for example i'll write

some pseudo code here so i have an

a number a a number b and

then say for example this is integer

integer and then there is another

integer

c and c is equal to a

plus b and then basically return

c so for example this is one of the

addition method that has been

implemented

as code right so if it is white box then

i know

that this is what the code has been

written for the additional functionality

similarly i'll have access

to the code that is implemented for the

multiplication for division

and similar will be the case in the

actual applications the complex

application say for example e-commerce

website

you will have access to the actual code

or the methods that are written

to perform a particular functionality or

the requirement if you're testing that

and you are verifying

the code within it how the code behaves

then that it will be white box testing

now in this white box testing what i'll

do is now

because i have access to code as well

i'll try to

test this particular you know code with

valid values invalid values

so i'll try with float i'll try with you

know invalid numbers

i'll try with with passing all other you

know negative scenarios and see

how this particular code behaves whether

it just

accepts integers and returns the integer

you know sum or multiplication etc

or it crashes if i provide some invalid

value

right so when you do this type of you

know verification

then that is white box testing i think

white box testing there are many

techniques so basically statement

coverage

so there are many types of testing so

the

statement coverage when you cover each

and every

you write the test case so that you

verify that the

statements all the statements in the

code are being covered

that is known as statement coverage um

then you have you know condition

coverage

loop coverage um and then you know like

paths testing or loop testing so all

those type of testing

will be part of the white box just

testing now let me write some of those

here as well so that you know so there

is statement

coverage and

the second important one is the branch

coverage

so when you verify the branch

the third important one to remember is

the condition coverage

then you have the loop

testing so you verify there are loops

different loops then you verify all the

loops are being exercised

with your test cases and then you have

you know path so different path testing

if there are multiple paths

say for example you have conditions then

you verify all those conditions right

so these are some of the techniques or

basically the coverage technique that

you will verify

and there are a lot of code coverage

tools available so when you write your

white box test cases

you most of the time this will be done

by the developers but as a tester

you will be required to basically

provide your inputs or

in case you know white box testing or

need to do in your organization then you

need to cover all this

you know white box testing techniques

you need to verify

that the code coverage or your test

cases have

or provide you the coverage of statement

branch condition

you know loop path all the code is being

exercised

in the white box testing now usually

you know white box testing will happen

uh in the unit test phase

okay so unit testing phase uh is where

the white box testing happens as well as

in the integration

testing okay so integration testing

it can happen in both phases because in

unit testing there will be small units

where which will be you know which

usually developers write the unit test

cases for and

there are you know unit test tools um

for example unit test framework for

example junit is very popular for java

and then integration testing you

integrate the units and make sure

after integration all these you know

statement branch coverage condition

coverage

loop and path testing is being done at

all

different levels all right so this is a

brief about

white box testing when you have

understanding and when you have

visibility of

what exactly happens when you

perform any operation or function on a

particular application in this case the

calculator when i press a

when i you know try to add two numbers

what exactly happens

within the code then that is white box

testing if

i don't have visibility of what happens

within the code

then that is known as black box testing

okay

so this is a brief about the white box

testing another example is of the

e-commerce

website so when i click on register link

after clicking on register link which

function got called

if i have the you know details or i have

the access to the actual code

when i click on register i can go into

the development

id and verify which

method got called and after that which

method got called

then that type of coverage and details

if i am verifying

with different test scenarios that i

write as part of the unit test or

integration test

in my code then that is white box

testing

all right so that's pretty much all

about the white box testing what white

box testing is

um different types of testing so

basically unit testing integration

testing you can do different

you know white box testing at different

levels

and then these are some of the coverage

or

the white box testing techniques that

will be utilized

in the white box testing so that's all

for this tutorial

hope it was helpful please do share and

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watching