What Is Unit Testing?
Unit testing is a software development process in which the smallest testable parts of an application known as units are individually and independently scrutinized for proper operation. This process can be done manually but it is usually automated.
Unit testing involves only those characteristics that are vital to the performance of the unit under test. This eventually encourages developers to modify the source code without immediate concerns about how such changes might affect the functioning of other units or the program as a whole.
What Is System Testing?
System testing also referred to as system-level tests is conducted on a complete integrated system to evaluate the system’s compliance with its specified requirements. System testing takes, as its input, all of the integrated components that have passed integration testing.
With system testing, the testing team determines whether a test case corresponds to each of an application’s most crucial requirements and user stories. These individual test cases determine the overall test coverage for an application and help the team detect critical faults that affect an application’s core functions before release.
Difference Between Unit Testing And System Testing In Tabular Form
| BASIS OF COMPARISON | UNIT TESTING | SYSTEM TESTING |
| Description | Unit testing is a level of software testing whereby individual units of source code, sets of one or more computer program modules together with associated control data, usage procedures and operating procedures are tested to determine whether they are ready for use. | System testing is a level of software testing whereby complete and fully integrated software is tasted. The purpose of system testing is to evaluate the system’s compliance with the specified requirements. |
| Main Focus | Unit testing entails testing independent software modules separately. The main focus of the test is to validate that each unit of the software works as designed. | The main focus of system testing is to evaluate business/ functional/ End-user requirements. All modules/components are integrated in order to verify if the system works as expected or not. |
| The Process of Testing | Unit testing does not have steep learning curve, the development team needs to learn what unit is, how to use automated software tools to facilitate the process on an on-going basis. | System testing entails steep learning curve. The development team determines whether a test case corresponds to each of an application’s most crucial requirements and user stories. The team can log and tabulate each defect per requirement. |
| Testing Framework | Unit testing framework include: NUnit JUnit TestNG Embunit HtmlUnit | System testing framework include: Frologic’s Squish and inflectra’s spira test, robotium and SmartBear’s SoapUI. |
| Performed by | Unit testing is performed by the developers. | System testing is generally done by developers and testers. |
| Composition | Unit testing comprises of independent modules. | System testing comprises of system and integration testing. |
| Follows | Unit testing follows the specification of modules. | System testing follows the requirement specification. |