Unit Testing vs System Testing
An application or software program should undergo a thorough testing process to ensure that the application is working in the manner in which it was intended. There are different layers of testing processed involved, out of which two major types are Unit Testing and System Testing.
Though the two testing activities are considerably different, they both are important for application's flawless functionality. Two distinct roles in many software projects that are involved with testing are developers and testers. In this article we will focus on Unit Testing vs System Testing. We will review each testing type, phases and compare between the two of them.
What is Unit Testing?
Unit Testing is a type of software testing in which it tests the smallest testable unit of the code. It ensures that individual components function as intended. The name is derived from the fact that tests are done on a unit by unit basis.
The goal of Unit testing is to help reduce the cost of bug fixes, as this way, bugs or errors in the code level are identified early in the development lifecycle. Traditionally, unit testing was not considered part of the QA team responsibility, as it is mostly performed at the development phase of an application or a product and is typically performed by the software developer.
Unit Testing Phases:
Unit tests usually consist of four phases,
Planning and setting up the environment: Developers consider which units in the code they need to test, and how to execute all relevant functionality of each unit to test it effectively.
Writing the test cases and scripts: Developers write the unit test code and prepare the scripts to execute the code.
Executing the unit testing: The unit test runs and reveals how the code behaves for each test case.
Analyzing the results: Developers can identify errors or issues in the code and fix them.
Unit Testing Tools:
Below are some major players of unit testing tools,
LambdaTest: AI-powered test orchestration and execution platform that equips developers and testers to perform automated unit testing
JUnit: JUnit is a Java driven open source unit testing tool used to test small/large units of code.
NUnit: NUnit is a . NET-based open source unit testing framework that has directly inherited most of its features from JUnit.
TestNG: It is a robust framework as we can have full control over the testing and execution of Test cases.
Mockito: Mockito is mainly used to mock interfaces so that dummy functionalities can be added to mock interfaces for unit testing.
What is System Testing?
System testing, as its name implies, verifies that overall functionality of the software or application is working as intended. It is a broader type of testing that covers the whole functionality of the application and ensures the application meets the technical, functional or system requirements.
Traditionally, System testing considered part of the QA responsibility and its undertaken by independent testers who haven't played a role in developing the application. The goal at this level is to evaluate whether the system has complied with all of the outlined requirements and to see that it meets Quality Standards.
System Testing Phases:
Below are the phases of System Testing,
Test Planning: This phase involves defining the scope, objectives, resources, schedule, and testing approach for the system testing process. It sets the groundwork for the entire testing effort.
Test Design: During this phase, testers create detailed test cases based on the requirements and specifications. Test scenarios are designed to cover all aspects of the system, including edge cases.
Test Environment Setup: In this step, the testing environment is prepared to mirror the production environment as closely as possible. This includes configuring hardware, software, and network settings.
Test Execution: Testers execute the designed test cases in the prepared environment, recording the results and any defects discovered during the process. This phase may involve manual testing or automated scripts.
Test Closure: After testing is complete, the team evaluates the results, reports defects, and assesses whether the system meets the acceptance criteria. A final report is created to summarize the testing efforts and outcomes.
System Testing Tools:
Below are some of the popular tools used for System Testing,
Selenium: Selenium is an open-source tool for automating web browsers. It supports various programming languages and can simulate user interactions
Apache JMeter: It is a powerful open-source tool for performance and load testing of web applications.
TestComplete: TestComplete is a commercial tool for automated UI testing of desktop, web, and mobile applications.
Postman: Postman is a widely used tool for API testing that allows developers to create and execute HTTP requests.
LoadRunner: LoadRunner is a commercial performance testing tool that simulates virtual users to test application performance under load.
Key Differences:
System Testing will help to verify the overall functionality of the application while Unit Testing is a testing method by which individual units of code are tested.
System Testing requires a high level of familiarity of the system’s structure whereas Unit Testing requires a familiarity of individual component.
In System Testing, test cases are built to emulate real-world conditions but Unit Testing requires test data for a specific function or a component.
Issues found in Unit Testing can be instantly fixed but issues found in System Testing take a longer time and the cost to fix is higher, as it becomes difficult to find where exactly a bug has arisen.
Unit Testing is a kind of white box testing, whereas System Testing is a kind of black-box testing.
For Unit Testing, accessibility of code is required, as it tests the written code, while for System Testing, access to code is not required, since it tests the application's technical, functional requirements.
Unit Testing is done by the developer who knows the product code. System Testing carried out by separate team of testers having complete knowledge of the application.
Key Similarities:
Both the Unit Test and System Test are very important and useful. Neither of these two tests can be considered more important than the other.
Both unit and system testing benefit from automation, allowing for faster and more thorough testing.
They should be performed rigorously, on time and should always be an integral part of the development process. It is always important to remember that both tests are correlated.
Summary:
Both Unit testing and System testing are essential elements when conducting software testing. Combining both types, and more specifically orchestrating the results of both testing types using a test management platform can help increase the overall testing visibility, which will enable the release of better quality products.
