Testing levels are very important these levels are normally recognize absent sections and stop the overlapping and recurrence between the all phases of development life cycle. As we know that in the software development life cycle models, there are determined many phases as requirement analysis and requirement gathering, designing, coding, testing, deployment. Every phases proceeds over the testing stage. So there are many categories or levels of the testing.

Below are the mentioned different-different software testing levels:-    

• Unit Testing
• Component Testing
• Integration Testing
• Component Integration Testing
• System Integration Testing
• System Testing
• Acceptance Testing
• Alpha Testing
• Beta Testing      

Unit Testing:- Unit testing is normally performed by the developers to assure that there written pieces of code are acting or working excellent and fulfill the user’s requirements or specifications. In the unit testing developers tests there code which are written by them as functions, classes, procedures etc.

Component Testing:- Component testing is also known as the module testing. There is a difference between the unit testing and component testing that is, in the unit testing developers verifies there pieces of code but in the component testing entire section or portion is verified or tested.

Integration Testing:- We performed the integration testing while two modules are integrated for verifying the functionality and behavior of both components or modules later the integration. Following are the few types of integration testing--

A- Top Down

B- Bottom Up

C- Big Bang Integration Testing

D- Functional Incremental  

Component Integration Testing:- In this testing either the modules or components are integrated, it’s known as the component integration testing. Generally this kind of testing is performed to assure that the code should not split later on the integrating of two modules.

System Integration Testing:- In the system integration testing testers normally verify in the similar environment all the associated systems should keep the data integrity.

System Testing:- Under the system testing test engineers normally verify the compatibility of the software or  application with respect to the system.

Acceptance Testing:- This type of testing is normally performed to assure that all the requirements of  the stipulation are completed.

Alpha Testing:- Alpha testing is normally performed at the development site. This type of testing is executed after the completion of development process.

Beta Testing:- Beta testing is normally performed at the client site. This type of testing is executed just ahead the launching of the software or product.