Why is Unit Testing Important in Software Testing?

PRAJUL P P | February 08, 2023

Why is Unit Testing Important in Software Testing?

Unit testing is a testing method using which every independent module is tested to determine if there is an issue by the developer himself. It's very important testing in SDLC because software developers sometimes try to save time doing minimal unit testing this is a myth because inappropriate unit testing leads to high-cost defect fixing during Integration Testing, System Testing, and Beta Testing after the application is built. It's a white box testing technique that is performed by the developer. Though, due to the time crunch of developers to test, QA engineers also do unit testing.

During, the SDLC, unit testing is the first level of testing. Testers know the internal design of the software in unit testing. Requirement database access and more hardware resources and other external dependencies are also needed for end-to-end tests. Developers write a section of code in the application just to test the function and they would later comment out and finally remove the test code when the application is deployed.

The Unit Testing Techniques are mainly categorized into three parts, Black box testing, White box testing, and gray box testing. Black box testing involves testing of the user interface along with input and output, White box testing involves testing the functional behavior of the software application, and Gray box testing is used to execute test methods, test cases, and test suites and perform risk analysis.

Unit Testing Tools

  • JUnit: It's a free-to-use testing tool used for the Java programming language. It provides assertions to identify the test method and this tool test data first and then inserted it in the piece of code
  • NUnit: NUnit is an open-source tool that allows writing scripts manually and its a widely used unit-testing framework for all .net languages and supports data-driven tests which can run in parallel.
  • JMockit: JMockit is a code coverage tool with line and path metrics and it's an open source Unit testing tool. It allows mocking API with verification syntax and recording. This tool offers data coverage, line Coverage, and path Coverage.
  • EMMA: It supports coverage types like method and basic blocking. EMMA is an open-source toolkit for analyzing and reporting code written in Java language so it is without external library dependencies and can access the source code.
  • PHPUnit: It takes small portions of code which is called units and tests each of them separately this tool is for PHP programmers. It also allows developers to use pre-define assertion methods to assert a system behaves in a certain manner.

Unit Testing Advantages

  • Developers who want to learn what a unit does and how to use it might look at the unit tests to better understand the API.
  • Unit testing enables the programmer to improve the code and confirm that the module functions correctly.
  • Unit testing enables testing parts of the project without waiting for other parts to be completed.
  • Unit testing helps simplify the debugging process and if a test fails then only the latest changes made in code need to be debugged.

Unit Testing Disadvantages

  • By definition, unit testing focuses on a single piece of software. This makes it incapable of detecting system-wide or integration issues.
  • Evaluating all execution paths is not possible in unit testing, so unit testing cannot catch every error in a program.
  • Testing works best when combined with other testing activities.
  • In simple cases, you lose about 20% of the actual implementation, but in complicated cases, you lose much more. If you correctly follow TDD it will save you time later in the long-term perspective.
  • The high-level design is not clear at the start and this will force you to completely redo your test which will generate a big time loss.

Why Should You Choose Sanesquare for Unit Testing?

Sanesquare has a team of experts who specialize in software development and testing, ensuring that your unit tests are performed thoroughly and accurately. Sanesquare has the necessary resources, such as tools and technologies, to perform effective unit testing. Sanesquare can provide a fresh perspective and catch errors that may have been overlooked in-house, leading to improved quality of your software.


We have given a detailed description of Unit Testing knowledge, the importance of why we need unit testing, and how it works, Also discussed various tools used in unit testing. We provide the best unit testing services with a team of QA experts at the Sanesquare Technologies. If you have any questions or comments, you can contact us.

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