Difference in different testing techniq
1) what is the difference between Unit testing, Integration testing and System testing?
2) what kinds of uniq bug can be found in individual testing technic which cannot be found in other testing technic
Unit - In isolation, using mock and stubs. Easy to have objective coverage metrics via code coverage, runs very fast, and easy to do (although adds to development time)
Originally Posted by Santosha kumar
Integration - Testing class/module interactions. Tests interactions between different classes/modules. Can detect bugs that have deal with misaligned expectations between classes/modules.
System - At a library or application level. Good at detecting configuration and integration with 3rd party
Unit testing is performed to check whether the small piece of code is working as expected to do.This test checks a single component of an application.
Integration testing is a type of testing to check whether different pieces of the modules are working together.
System testing is the final test of a complete application or product whether it is fulfilling the requirements and specifications.System testing consumes all of the "integrated" software modules that cleared integration testing and also the software system itself
Unit testing, also known as component testing, refers to tests that verify the functionality of a specific section of code, usually at the function level. In an object-oriented environment, this is usually at the class level, and the minimal unit tests include the constructors and destructors
These types of tests are usually written by developers as they work on code (white-box style), to ensure that the specific function is working as expected. One function might have multiple tests, to catch corner cases or other branches in the code. Unit testing alone cannot verify the functionality of a piece of software, but rather is used to ensure that the building blocks of the software work independently from each other.
Due to better understanding i am using 3 posts for that
Integration testing is any type of software testing that seeks to verify the interfaces between components against a software design. Software components may be integrated in an iterative way or all together ("big bang"). Normally the former is considered a better practice since it allows interface issues to be located more quickly and fixed.
Integration testing works to expose defects in the interfaces and interaction between integrated components (modules). Progressively larger groups of tested software components corresponding to elements of the architectural design are integrated and tested until the software works as a system.
System testing of software or hardware is testing conducted on a complete, integrated system to evaluate the system's compliance with its specified requirements. System testing falls within the scope of black-box testing, and as such, should require no knowledge of the inner design of the code or logic.
As a rule, system testing takes, as its input, all of the "integrated" software components that have passed integration testing and also the software system itself integrated with any applicable hardware system(s). The purpose of integration testing is to detect any inconsistencies between the software units that are integrated together (called assemblages) or between any of the assemblages and the hardware. System testing is a more limited type of testing; it seeks to detect defects both within the "inter-assemblages" and also within the system as a whole.
The technique of testing without having any knowledge of the interior workings of the application is called black-box testing.
Please find below details on Unit testing, Integration testing and System testing types:
This type of testing is performed by a developer majority of times. This type of testing is performed to check if the small piece of code is doing what it is supposed to do. The scope of Unit testing is narrow, it covers the Unit or small piece of code under test. Therefore while writing a unit test, shorter codes are used that target just a single class and defects found while debugging are related to logic.
Integration testing a type of manual testing and every software testing company which provides manual testing as QA services performs this type of testing. This type of testing is performed to check if different pieces of the modules are working together in perfect synchronization. The scope of Integration testing is wide, it covers the whole application under test and it requires much more effort to put together. This type of testing is carried out after Unit testing and before System testing and executed by the testing team.
Defects found are related to synchronization and information flow.
The system testing comes under black box software testing and can be both functional and non-functional type of testing. In this type of testing focus is more on the functionality of the system as a whole and knowledge of internal design, structure or code is not required. The behavior of the complete application is tested to check if it meets the specified requirements and the company providing software testing services and automated testing services, always performs this type of testing.
All types of functional defects are found by this testing type.
Please let me know if still you have any doubt and I will be more than happy to resolve them.
I think most everyone here gave you the correct answers.
it's a "hot topic" you can read about it here: Manual Testing Introduction - Softwaretestingtools.com