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Table of contents
SDLC (Software Development Life Cycle)
STLC (Software Testing Life Cycle)
Black Box Testing
Functional Testing
Non-Functional Testing
Regression Testing
Non-functional Tests 
Frequently Asked Questions
What is the main principle of software testing?
Who will perform black box testing?
Is black box testing dynamic?
Is the Grey box testing technique related to black box testing techniques?
Which test cases can be automated?
Last Updated: Mar 27, 2024

Black-Box Testing

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Prerita Agarwal
Data Specialist @
23 Jul, 2024 @ 01:30 PM


Everybody uses some or other applications daily. But have you wondered how the entire software runs? How are the input and output generated? Why do we update the software? All this is covered under software testing.

Black-Box Testing og

In this blog, we will be studying one such testing called black box testing. 

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SDLC (Software Development Life Cycle)

A framework known as the Software Development Life Cycle (SDLC) draws the steps that must be followed throughout each phase of software development. 

SDLC (Software Development Life Cycle)

It includes a clear outline of the strategy for creating, deploying, and maintaining the software application program. This framework helps the product to be completed faster and reduces risks.

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STLC (Software Testing Life Cycle)

Software Testing is a procedure to assess a software's functioning. It helps determine if the created software satisfies the requirements so that a quality product may be produced.

STLC (Software Testing Life Cycle)

Testing is about finding software errors, faults, and incidents. A test is running the software using test cases. A test always has two clear goals. One is finding failures, and the other is completing the execution correctly.

An identity and a connection to program behaviour define a test case. A test case has several predicted outcomes as well as inputs.

Black Box Testing

Black Box testing is Functional testing. Functional testing is wherein each program may be viewed as a function that maps values from the input domain to values within the output range. This leads to the term Black Box Testing, in which a black box's content and execution are unknown.

Black Box Testing


Black Box Testing is where the program is tested without knowing how it is coded and structured. The tester is only aware of the inputs and expected outputs. Therefore performs the testing from the user's viewpoint. It is still being decided by the tester how the software processes requests and results.

Let's take the example of testing a music player to see if it works as expected. We can examine whether the user can play a song, pause it, play the next song, or play the previous song. They also test other features, such as creating a playlist, searching, removing it from a playlist, etc.

Read more about Software Engineering here. 


Any program can be considered a function because it inputs from its domain and program output from its range. Input domain testing is the best-known functional testing. Some of these techniques are

  • Equivalence Class: It provides enough coverage for testing while optimally reducing the number of potential test cases. Expected values from each type are selected for testing. This speeds up the process while holding test coverage and reducing rework.
  • Boundary Value Analysis: The boundary value analysis tests the limits of input values in an application. Here we can understand whether the system behaves differently at limit values, known as boundary values (including valid and invalid inputs).
  • Domain Tests: Domain testing involves thinking of ways to test a specific function. We can then group the tests into smaller groups. Next, we can go through each subset one by one.
  • Orthogonal arrays: A pair-wise interaction can be tested using orthogonal arrays in order and statistically. It is achieved by interpreting and prioritising factors.
  • Decision Tables: This technique is suitable for conditions where the functionalities have logical input. This technique uses inputs as conditions and outputs as actions.
  • State Models: This technique considers inputs and outputs in the testing phase. It tests an application for a sequence of transitions of test inputs. This technique helps to check the system's behaviour changes.
  • Graphical Testing: There are many different types of testing software. The test case can be created by building relationships between objects from the graphical data. With the help of feeding inputs and monitoring the response, a cause-and-effect graph can be derived.
  • Exploratory Testing: Testers conduct experimental tests by analysing and noting applications for potential bugs. They conduct analysis and discovery to test a product successfully.
  • All-pair Testing: This technique tests software using a blended method. Here all the different parameters are independently tested.


The different types of black box testing are functional, non-functional, and regression testing.

Functional Testing

Functional testing is related to the functional requirements of a software system. When a system is examined for how well it performs its functions, the tester will have a user perspective in mind.

It focuses on the functional part of the application. Input and output are the only things that matter. The tester acts as if they are the final user of the program. Mainly suitable for higher levels of testing, such as Acceptance Testing and System Testing. 

They are independent of how the software is implemented, so the test cases are still helpful if the implementation changes. Test case development can occur parallel with the implementation. This reduces the overall project development interval.

There can be significant redundancies among test cases. The possibility of gaps in untested software compounds it.

Non-Functional Testing

Testing that considers other criteria, such as load tests, scalability tests, and stress tests, is called non-functional testing. It evaluates how well an application will perform under challenging conditions. 

Regression Testing

Regression testing aims to determine if the new changes have not affected prior work. It checks any existing functionality after code fixes, upgrades, or other forms of system maintenance have not been affected.


Here are the steps for testing:

Step 1: Understanding the requirements specifications. This should be reflected in the requirements specification document.

Step 2: It is time to evaluate the software's inputs and scenarios. It will save time and will achieve good test coverage.

Step 3: Design test cases to cover various input conditions.

Step 4: The system's output is generated and compared with the expected outcome while running the test case. It helps mark the test as successful or unsuccessful.

Step 5: When steps fail, they are marked so the development team can fix them.

Step 6: Using various testing techniques, retest the system to ensure recurring or passes.

Software development life cycles can easily be tested and validated using black box testing.


Various levels, such as unit, integration, acceptance, system, and regression testing, can be accomplished in the black box testing.

  • Unit Testing: This phase decides how the software's interface will interact. It checks interactions with the specifications the client offers before implementation.
  • Integration Testing: Integration testing inspects software interactions among integrated components. It also determines if issues and errors occur.
  • System Testing: It does not require knowledge of the software's internal design or code. It evaluates the system against the client's specifications.
  • Acceptance Testing: This testing tests the software in unanticipated and unexpected situations.
  • Regression TestingRegression testing aims to determine if the new changes have not affected prior work. It checks any existing functionality after code fixes, upgrades, or other forms of system maintenance have not been affected.

Also check out - Phases of Compiler


The most favourable feature of black box testing is automating it. It simplifies the process and maximizes accuracy. Furthermore, it allows the process to be flexible and comprehensive.
Testing tools are categorized into different categories:

SNo. Name Logo Description

HP QTP automates applications with Visual Basic Scripting (VBScript). This tool seamlessly helps testers perform automatic functional testing without monitoring.
2 Selenium

Web browser automation tool Selenium automates browsers through an open-source tool. It offers a single interface that can be used to write test scripts in Ruby, Java, NodeJS, PHP, Perl, Python, and C#.
3 SoapUI

It automates SOAP and REST API test scenarios. API Tests can be written, run, integrated, and easily automated.
4 Cucumber

It is a ruby software testing tool written in open source. Cucumber allows the creation of test cases. These can be easily understood, regardless of technical knowledge.
5 Watir (Web Application Testing in Ruby)

It is an open-source tool developed using Ruby. It simplifies test automation for web applications of all languages.

Non-functional Tests 

SNo. Name Logo Description
1 Loadrunner

Performance and load tests can be performed for various environments and protocols using LoadRunner Professional. Web/Mobile, Web services, MQTTHTML5, Web sockets, Remote Desktop, Remote Terminal Emulator, Citrix, Java, .NET, Oracle, and SAP can all be tested. 
2 Jmeter

Applications, various software services, and other items' performance are examined and measured using an Apache tool.
3 Loadtracer

It is a GUI-based tool for testing web applications under load, stress, and scalability.
4 LoadComplete

This tool helps create and use automated load tests for web servers and services.
5 NeoLoad

NeoLoad analyses your server behaviour by simulating many user actions during testing.
6 Silk Performer

This is a load testing and web performance tool. It tests the performance and scalability of web applications.
7 WebLoad Performer

This tool is used for load testing, performance testing, and stress testing web applications.


  • Testers are not required to know an application's entire coding language or execution details.
  • Once the functional specifications are ready, it can create test cases.
  • Projects can be completed more quickly and with less effort. 
  • The test cases generated in black box testing can be used for testing similar functionality in other applications.
  • Projects are successful when end-users conduct black box testing (acceptance or beta testing).


  • It is impossible to test every aspect of the application.
  • Increases the debugging time.
  • Many of the test cases could be more straightforward and more precise. 
  • Many of the paths in the program still need to be tested.
  • Designing test cases requires understanding the application's internal structure.
  • Test cases may be repetitive.

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Frequently Asked Questions

What is the main principle of software testing?

The main principle of software testing states that testing should start from smaller components and move on to larger ones.

Who will perform black box testing?

Independent testing teams perform this testing during the software testing life cycle.

Is black box testing dynamic?

Dynamic testing is usually used in black box testing. The typical image of a software tester is that they run the code and then record any errors they find. We call this dynamic black box testing.

Is the Grey box testing technique related to black box testing techniques?

Grey box testing combines black box and white box testing techniques.

Which test cases can be automated?

Test cases that can be automated are Smoke test cases, Regression test cases, Complex calculation test cases, Data-driven test cases, and Non-functional test cases.


In this article, we have discussed what black box testing is. We have also discussed the different steps and techniques used in black box testing. After reading about the Black Box testing, are you not feeling excited to read/explore more articles on software testing? Don't worry; Coding Ninjas has you covered. To learn more about software testing, read the following blogs.

You may refer to our Guided Path on Code Studios for enhancing your skill set on DSACompetitive ProgrammingSystem Design, etc. Check out essential interview questions, practice our available mock tests, look at the interview bundle for interview preparations, and so much more!

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