Levels of Testing - Software Testing Levels

To avoid overlapping and repetition between the development life cycles testing levels are used.
Various phases of SDLC are Requirement Collection, Designing, coding,testing, deployment and maintanence.
Application that needs to be tested should go through all the phases of SDLC.
Multiple levels of testing are performed so that it helps us to maintain the quality of the software.
Levels of Software Testing are:
- Unit Testing
- Integration Testing
- System Testing
- Acceptance Testing

Levels of Testing

Unit Testing

The First type of testing is unit testing.
This type of testing is done to check if the software modules are satisfying the given requirement or not.
This level of testing is done by breaking the application into each units or components.
This is the first testing done under functional testing. The primary purpose of executing unit testing is to validate unit components with their performance.
The smallest testable part of the application or software is called unit or component.
This type of testing is done to test the correctness of inaccessible code.
Unit testing will help the test engineer and developers in order to understand the base of code that makes them able to change defect causing code quickly. The developers implement the unit.

Unit Testing

Integration testing is the second level of software testing.
This testing is performed after unit testing.
Data flow from one module to another module is tested here.
Units or components or modules of the software are tested in a group by the test engineer.
Integration testing is performed to identify the defects at the interactions between the integrated components or units.
The process of checking the data flow between dependent modules when each component or module works seperately is known as Integration Testing.
Integration testing is performed only after the completion of functional testing successfully on each application module.
Main purpose of integration testing is to evaluate the accuracy of the communication among all the modules.

Integration Testing

System testing the third level of testing which is used to test the software functional and non functional requirements.
It is end-to-end testing where the testing environment is parallel to the production environment.
This a level of testing where the application is tested as a whole system.
System testing is done to check the end to end flow of an application or software.
All the neccessary modules of the software are tested to check if its features works fine.
In simple words, we can say that System testing is a sequence of different types of tests to implement and examine the entire working of an integrated software computer system against requirements.

System Testing

This is the last level of the software testing which is used to check whether a specification or requirements met its delivery.
In simple words, we can say that System testing is a sequence of different types of tests to implement and examine the entire working of an integrated software computer system against requirements.
Before performing acceptance testing the software has to go through three levels(unit, integration, system) of testing.
When the end user performs acceptance testing in actual scenario some minor errors can still be found.
Squeezing of all the testing process that was done previously is known as acceptance testing.
Acceptance testing is also known as User Acceptance testing and this type of testing is performed by the customer before accepting the final product.
As mentioned customer performs these type of testing to check whether the application works according to the buisness requirements and real time scenarios.

Acceptance Testing