Integration Testing

Integration testing is intended to test communication between components, as well as interaction with various parts of the system (operating system, hardware, or communication between various systems).

Levels of integration testing:

• • Component Integration testing

The interaction between the system components after component testing is checked.

• System Integration Level ( System Integration Testing )

  The interaction between different systems after system testing is checked.

Approaches to integration testing:

• • Bottom Up Integration

All low-level modules, procedures, or functions are put together and then tested. After that, the next level of modules is collected for integration testing. This approach is considered useful if all or practically all modules of the developed level are ready. Also, this approach helps to determine the level of readiness of the application by results of testing (see also Integration testing - Bottom Up)

• • Top Down Integration

First, all high-level modules are tested, and low-level ones are gradually added one by one. All modules of a lower level are simulated by plugs with similar functionality, then as they become ready, they are replaced by real active components. So we are testing from top to bottom. (see also Top Down Integration)

• • Big Bang ( "Big Bang" Integration )

All or almost all developed modules come together as a complete system or its main part, and then integration testing is carried out. This approach is very good for saving time. However, if test cases and their results are not recorded correctly, the integration process itself will become very complicated, which will be an obstacle for the testing team to achieve the main goal of integration testing (see also Integration testing - Big Bang)