Integration Testing

What Does Integration Testing Mean?

Integration testing is a software testing methodology used to test individual software components or units of code to verify interaction between various software components and detect interface defects. Components are tested as a single group or organized in an iterative manner. After the integration testing has been performed on the components, they are readily available for system testing.


Techopedia Explains Integration Testing

Integration is a key software development life cycle (SDLC) strategy. Generally, small software systems are integrated and tested in a single phase, whereas larger systems involve several integration phases to build a complete system, such as integrating modules into low-level subsystems for integration with larger subsystems. Integration testing encompasses all aspects of a software system’s performance, functionality and reliability.

Most unit-tested software systems are comprised of integrated components that are tested for error isolation due to grouping. Module details are presumed accurate, but prior to integration testing, each module is separately tested via partial component implementation, also known as a stub.

The three main integration testing strategies are as follows:

  • Big Bang: Involves integrating the modules to build a complete software system. This is considered a high-risk approach because it requires proper documentation to prevent failure.
  • Bottom-Up: Involves low-level component testing, followed by high-level components. Testing continues until all hierarchical components are tested. Bottom-up testing facilitates efficient error detection.
  • Top-Down: Involves testing the top integrated modules first. Subsystems are tested individually. Top-down testing facilitates detection of lost module branch links.

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