Discuss the following approaches to software testing (8 Marks )i. Functional testingii. Structural testingiii. Integration testingiv. Component Testing

i. Functional Testing: This is a type of black-box testing that is based on the specifications of the software that is to be tested. The application is tested by providing input and then the results are examined that need to conform to the functionality it was intended for. It involves checking of User Interface, APIs, Database, security, client/ server applications and functionality of the Application Under Test. The purpose of functional testing is to ensure that the system is working as it should.

ii. Structural Testing: Also known as white box testing, this approach is based on the inner workings of an application and revolves around internal testing. The tester has knowledge of the internal software structure and based on this knowledge inputs are derived for testing. It involves checking of code that you have written, branch coverage, paths coverage, statement coverage etc. The purpose of structural testing is to improve the quality of a product and its robustness.

iii. Integration Testing: This type of testing is performed to expose defects in the interfaces and interaction between integrated components (modules). It is basically the testing of the interaction between different software modules. It can be conducted in the form of top-down, bottom-up, sandwich and risk-based approaches. The purpose of integration testing is to ensure different components of the application interact with each other. Tools like Junit, NUnit are used for this type of testing.

iv. Component Testing: Also known as module, unit or program testing, this approach looks at the smallest part of an application separately. In this type of testing, the individual software components are tested. This testing is performed after the completion of unit testing. Component testing helps to identify any errors in the early stages of the development cycle, making it easier to rectify them. The purpose of component testing is to ensure that each component functions as it should.

i. Functional Testing: This is a type of black-box testing that is based on the specifications of the software that is to be tested. The application is tested by providing input and then the results are examined that need to conform to the functionality it was intended for. It involves checking of User Interface, APIs, Database, security, client/ server applications and functionality of the Application Under Test. The purpose of functional testing is to ensure that the system is working as it should.

ii. Structural Testing: Also known as white box testing, this approach is based on the inner workings of an application and revolves around internal testing. The tester has knowledge of the internal software structure and based on this knowledge inputs are provided and the output is checked. It includes techniques like statement coverage, decision coverage, path coverage, and branch coverage.

iii. Integration Testing: This type of testing involves combining individual units of a program and testing them as a group. The purpose of this level of testing is to expose faults in the interaction between integrated units. It can be done in three ways: sandwich approach, top-down approach, and bottom-up approach.

iv. Component Testing: Also known as module or program testing, this approach tests the smallest element of the software that performs a specific activity and can be tested separately. This could be a specific function within a module of the software. The purpose of component testing is to ensure that each component functions as it should. This type of testing is usually performed by the developers in the development environment.