What are Levels of testing ?

We divide Testing In Four Level,Unit Testing,Integration Testing, System Testing and Acceptance Testing.

Unit testing:-

Generally the code which is generated is compiled. The unit test is white box oriented and the steps can be conducted in parallel for multiple components.

1. The module Interface is tested to ensure that information properly flows into and out of the program unit under test .
2. The local data structure is examined to ensure that data stored temporarily maintains its integrity during all steps in an algorithm’s execution.
3. Boundary conditions are tested to ensure that the module operates properly at boundaries established to limit and restrict processing.
4. All the statements are executed at least once and error handling paths are tested

Integration testing:-

Integration testing is a systematic technique for constructing the program structure .After Performing Unit Testing perform integration testing. you have like

Top down :-Top down integration testing with the main routine and one or two immediate subordinate routines in the system structure it is good to have modules are integrated as they are developed, top level interfaces are tested first.

Bottom up :-Bottom up integration testing is the traditional strategy used to integrate the components of a software system into a functioning whole

Regressive testing:- Retesting the already test modules and adding new modules .Regressive testing is an important strategy for reducing side effects.

System Level Testing :

System Testing is third level of Testing In this level we check Functionility of application.

Performance testing: - Performance testing is designed to test the run time performance of software or hardware.

Recovery testing :- is a system test forces the software to fail in a variety of ways and verifies that recovery is properly performed .if recovery is automatic, re initialization , check pointing ,data recovery and restart are evaluated for correctness.

Security Testing: - Security testing attempts to verify that protection mechanisms built into a system will in fact, protect it from improper penetration.

Acceptance Testing:- When customer software is built for one customer, a series of acceptance tests are conducted to enable the customer to validate all requirements. conducted by the end user rather than software engineers, an acceptance test can range from an informal test drive to a planned and systematically executed series of tests. If software is developed as a product to be used by many customers, it is impractical to perform acceptance tests with each one. Most software product builders use a process called alpha and beta testing to uncover errors that only the end user seems able to find