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Fundamentals of Test Harness

Fundamentals of Test Harness

December 7, 2022
Shinji KanaiShinji Kanai
Shinji Kanai


With people moving to a world more focused on digital products, software testing is becoming significant for enterprises to fulfill customer requirements. In advanced software testing methods, many systems and tools are used to make the testing process efficient. A test harness is a similar system used in the software testing cycle. A test harness is a system that contains a set of software, test data, test drivers, and tools, which are used to perform testing of applications under various environments. During the test harness process, the QA teams monitor the behavior and output, and a respective report is generated. It is considered one of the popular testing processes that enable QA experts to evaluate each app’s features in detail, perform tests, and generate a comprehensive report for developers. This report can support the development teams in analyzing the entire testing process and making changes per desired output.

Check out: 10 Ways to Accelerate the Software Testing Cycle

Key Advantages of the Test Harness System

Let's check some of the test harness system's advantages that support software development and testing.

1. Automation of the Testing Process

A test harness system supports QA teams in automating the overall testing process to the maximum extent. The execution engine is the main component of a test harness system. The execution engine is the automated system in a test harness system that performs all testing activities with the test scripts. With the automation of the testing process, a test harness system helps QA teams to shorten the testing cycle.

Also check: A Comprehensive Guide on Automated Testing

2. Collection of Test Scripts for Various Test Cases

The test repository in the test harness system contains test scripts for all test cases that are planned to be executed. This component of the system enables QA teams to execute test suites that are composed of multiple test cases. A test harness system also contains drivers and stubs, which are small programs capable of supporting debugging of code, even if some components of the application are under development.

Read: How to Write Automated Test Scripts Using Selenium

3. Generation of Detailed Test Reports

A test harness system helps development teams to generate test reports either through its system or through TestNG and other third-party tools. Development teams can get access to a detailed report about the testing cycle and processes involved. This report will help them to improve their development methods with effective steps.

Read: How ReportPortal Helps Continuous Integration and Testing Processes

Significance of Test Harness in Software Testing

In the software testing cycle, the test harness process helps QA experts in the automation of tests. A test harness system can enable the testing and development teams to monitor functions with supplied parameters and generate reports to compare the results to the desired value. A test harness system is considered as a support to the existing code, which is also tested using an automation testing framework. Here are some of the important factors for using the test harness system in the software testing cycle:

  • A test harness system helps the QA teams to choose the right path suitable for the app testing before performing the testing of any application.
  • It enables development teams to estimate the code coverage in the early stages of software testing.
  • By using stubs and drivers, a test harness system can support the QA process of a certain module of an application, even if the other modules are under development.
  • With a test harness system, QA experts can automate the entire testing process, thus helping to increase the overall productivity of the software testing cycle.
  • A test harness system is very useful for managing difficult conditions, like communication with various libraries and tasks that are complicated for testers.
  • Development teams can generate enhanced reports of the test results using a test harness system for comparing the test results.
  • A test harness system also helps QA teams in the debugging of the test cases executed simultaneously.
Please check: Unit Testing: A Comprehensive Guide

Role of the Test Harness​ System in Automation and Integration Testing

Automation Testing

A test harness system plays a vital role in the automation testing of applications. It offers test scripts written in programming languages like Java, Python, Ruby, etc., and the test data to perform the testing using the test scripts. It also helps developers gather the results of each test case with enhanced charts and reports for the test results, which can help development teams compare the actual and expected data.

Integration Testing

For performing an integration test, the code of all the modules should be ready to perform the test. However, this is not possible in a real-life scenario, as most of the time, other modules of the application are underdeveloped. Here comes the crucial role of a test harness system in integration testing. A test harness system provides stubs and drivers, which are the substitute code used in place of the undeveloped module. With the use of a test harness system in integration testing, it is possible to ensure that all modules involved in integration testing operate as a successful unit for each of the test cases.

Check out: JUnit: A Complete Guide

Major Differences Between Test Harness and Test Framework

Even QA experts get confused between a test harness system and a test framework. So, understanding the difference between them is very crucial for both development and QA teams. To better understand both processes, let’s check the major differences between a test harness system and a test framework.

Test Harness Test Framework
1. It is a specific tool. 1. It is a common and generic process.
2. It contains small dummy programs, like drivers and stubs, that interact with the software under development for testing purposes. 2. It is a set of processes, procedures, and environments where automated test cases are designed and performed.
3. It has all the necessary information to arrange and execute test cases, stubs, and source code files. 3. It mainly contains test libraries, testing platforms, and automated testing tools.
4. It does not support the ‘Record & Playback’ feature while testing. 4. It enables QA teams to manually perform the ‘Record and Playback’ of the script.

Examples of Test Harness Tools

The two important tools used in the test harness system are:

1. JUnit

​JUnit is an open-source framework in the Java language. It is used to develop and perform automated test cases. Specifically, it is used to execute the unit testing of the Java program or the applications written in the Java language.

2. NUnit

​Similar to JUnit, NUnit is also an open-source framework, but it is written in the .NET language. NUnit is used to develop and perform automated test cases. Moreover, it is mainly used in test-driven development (TDD).

Also read: Unit, Integration, and Functional Testing - The main differences

Integrate HeadSpin with Test Harness Tools for Effective Software Testing

As the main objective of using a test harness tool is to automate testing and improve test efficiency, HeadSpin is the best tool for QA teams to double the benefits of a test harness tool. With a focus on helping global enterprises to optimize and automate their testing procedures, HeadSpin offers a centralized testing platform with unique capabilities, including automated functional, performance, and load testing across applications, devices, and networks for mobile, web, IoT, and 5G. Let’s check some of the best-in-class features of the HeadSpin Platform that will help QA teams boost the advantages of test harness systems and overall test efficiency.

1. Data Science and AI Capabilities for Effective Software Testing

Using the data science capabilities of the HeadSpin Platform, QA teams can gather a large set of data about the software being tested. Also, they can collect secondary metrics, such as packet, code, and network visibility details, page load time, API, CDN, and third-party SDKs. At the same time, QA teams can use HeadSpin’s AI engine to pinpoint the possible errors a user can face and resolve them proactively. HeadSpin’s data science and AI capabilities can support global enterprises improve their testing efficiency.

2. End-to-End Automation Testing

With the HeadSpin Platform, global companies can execute end-to-end automated testing of software applications. QA teams can get end-to-end visibility and UX and functional assessments using the Platform. HeadSpin’s end-to-end automated testing feature can support organizations to increase and improve collaboration while using test harness tools across teams and team members. Moreover, with HeadSpin automation capabilities, global enterprises can enhance their test efficiency and coverage.

3. Global Device Infrastructure

HeadSpin maintains a global infrastructure of various devices, including mobile and desktop browsers, smart TVs, OTT devices, game consoles, and more, which are deployed across 90+ locations worldwide. With the help of the HeadSpin Platform, enterprises get access to thousands of real mobile and browser testing devices to execute testing of websites, native apps, and hybrid applications from various geographies.


In the complicated software testing world, a test harness system is an effective and valuable testing procedure to get insights into complex issues in software testing, improve productivity, and generate an extensive report that can support the development team resolve the problems proactively. With test harness tools, QA teams can deliver quality software products that are tested effectively right at the unit level. Thus, test harness tools can add confidence to both development and QA teams during the software development stages.

The combination of a test harness tool and the HeadSpin Platform is something that can help global organizations raise the level of their software testing by enhancing test coverage and business value.

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Q1. What is top-down integration testing?

Ans: Top-down integration testing is an integration testing method used to simulate the behavior of the lower-level modules that are under development.

Q2. What is test-driven development (TDD)?

Ans: Test-driven development is the testing method where test cases are written even before the code that evaluates those cases are developed.

Q3. What is record & playback in software testing?

Ans: Record & playback is a low-code method used in software testing that uses a tool to automate tests without writing test scripts.

Q4. Can you integrate the JUnit framework with the HeadSpin Platform?

Ans: Yes. The HeadSpin Platform supports all open-source frameworks. Testers can integrate the JUnit framework seamlessly with the HeadSpin Platform.

Fundamentals of Test Harness

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