Implementation & Unit Testing: Upon getting the system design specifications documentthe actual coding would be started. Before starting the actual coding requirements are divided into the models/units. In the actual coding the initially develop the small programs called units. After implementing all units the integration would be started in the next phase. The developed units model functionality is tested separately in this phase to chec! whether the unit models are meets the specified requirements " this individual model testing is called as Unit Testing.Integration & System Testing: In the previous model the system requirements are divided into models " each model is developed " tested separately. In this phase all units are integrated " done the system testing to chec! whether the all models/units are integrated properly or not " the system as whole doing as mention as per the system requirement document# so we call this phase as the Integration " $ystem Testing. Upon complete testing of software is done then actual $oftware is successfully send to customer.$ome common testing methodologies including unit testing# acceptance testing# functional testing# performance testing and security testing.%& Unit TestsThis is the most basic testing mechanism at the developer level. This covers very narrow and well defined scope. 'e isolate the code from any outside interaction or any dependencyon any module. Unit tests focus on very small unit of functionality. They cover the interaction of the code with memory only and do not cover any interaction with networ!# database or file systems. These dependencies are hard coded into the code while testing.They provide a simple way to chec! smallest units of code and prove that units can wor! perfectly in isolation. (owever# we need to chec! further that when these units are combined they wor! in a cohesive manner which leads us to further types of tests.)& Integration TestsIntegration Test forms the next class of tests at the developer level. They provide a mechanism to test the interoperation of smaller units. Integration test involve testing the modules which access networ!# databases and file systems. They reveal out the issues with networ! modules or databases and more importantly in the connections between small unitsof code. *ften when the units are wired together there are issues. Unit A might not be giving data properly to the Unit B and these issues come up in the integration tests.+& ,unctional TestsAfter the integration tests are performed# higher level tests are used. ,unctional tests chec! for the correctness of the output with respect to the input defined in the specification. -ot much emphasis is given on the intermediate values but more focus is given on the final output delivered..& $mo!e Tests$mo!e Tests analogy comes from the electronics where a mista!e means the circuit board giving out smo!e. After functional tests are done a simple test is done from the start typically after a fresh installation and newer input values. /uc!ily there is no smo!e in software industry but yeah# crashes are there to indicate trouble.0& 1egression Tests'henever complex bugs are patched in a system# typically which affect the core areas of the system# regression tests are used to re test all the modules of the system.2& Acceptance TestsThese form the final level of test plan. 3very feature is chec!ed from the users perspective by the testing team and the feature is mar!ed accepted or re4ected. These tests test the application from end users perspective li!e detecting crashes after going through a certain flow. The results of these tests are very sub4ective in nature and it ta!es a while to figure out the exact issue in the code.