Testing is the process of evaluating a software or a application with the intent to find whether it satisfies the specified requirements or not. Testing can be defined as a process of analyzing a software item to detect the differences between existing and required conditions nothing but defects or errors or bugs .

In the IT industry, large companies have a team with responsibilities to classify the developed software. Moreover, developers also conduct testing which is called Unit Testing. In more cases, the following experts are involved in testing a software:
* Software Tester
* Software Developer
* Project Lead/Manager
* End User

When to Start Testing?

In Software Development Life Cycle , testing can be started from the Gathering Requirements phase and continued untill the deployment of the software. Testing is done in various forms at every phase of SDLC:
* During the requirement gathering phase, the verification and analysis of requirements are also treated as testing.
* Reviewing the design in the design phase, with the alert to improve the design is also considered as testing.
* Testing performed by a developer on integration of the code is also categorized as testing.

When to Stop Testing?

A testing is a never-ending process and no one can claim that a software is 100% tested. The following aspects are to be designed for stopping the testing process:
* Completion of test case execution
* Completion of functional and code coverage to a certain point
* Testing Deadlines
* Bug rate falls below a certain level and no high-priority bugs are identified
* Management decision

Test levels

Acceptance testing:„ Testing in the customers environment, by the custtomer

System testing: „ Test of functionality and performance of software against requirements and customer requests and against requirements specification

Integration testing:„ During step-by- step combination of the modules of a software to a whole system. Testing of correct interaction and communication between modules with Against interface specifications

Module / Unit testing: „ Isolated check of a single module . Test of correct and complete realization of the module specification with against unit specifications