Difference Between Top-down and bottom-up Integration Testing

Automation TestingSoftware TestingTesting Tools

In this post, we will understand the difference between top-down integration testing and bottom-up integration testing −

Top-down Integration Testing

  • It is also known as incremental integration testing.

  • The higher level modules are first tested after which the lower level modules are tested.

  • Once it is done, they are integrated.

  • The higher level modules are the main modules and the lower level modules are the submodules.

  • It uses stubs to simulate the sub-modules.

  • If the sub-module hasn’t been fully developed, the stub acts like a replacement to it.

  • It is useful in cases where significant defect occurs at the top of the program.

  • The main module is designed first and then the submodules or subroutines are called from it.

  • It is implemented on structure or procedure-oriented programming languages.

  • It is a simple testing technique.

  • It works on big to small components.

  • Stub modules need to be produced.

Here’s the flow diagram for stub −

Bottom-up Integration Testing

  • The lower level modules are tested first after which the higher level modules are tested.

  • The lower level modules are the sub-modules and higher level modules are the main modules.

  • It uses test drivers to initiate and pass the required data to the sub-modules.

  • The test drivers are used to simulate the main module.

  • If the main module hasn’t been developed yet, the driver works as a replacement to it.

  • It is useful in cases where the crucial flaws are identified at the bottom of the program.

  • It is generally implemented on object-oriented programming languages.

  • It is highly complex and data intensive.

  • It works on small to big components.

  • The driver modules need to be produced.

Here’s the flow diagram −

raja
Published on 29-Apr-2021 06:20:50
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