Top-down integration testing is an integration testing technique. It is used in order to simulate the behavior of the lower-level modules. Stubs are the modules that act as temporary replacement for a called module and give the same output as that of the actual product.
What is Top-Down Integration Testing
The top-down testing enables one to accept and expect that outlining and testing can be covered. Which may not be the situation and in conclusion. It initiates one to concede fruition of the testing of specific modules. Thinking of it as is constantly great to advance the product and test software in pieces. Top-down integration testing is an integration testing technique. Stubs are the modules that act as temporary replacement for a called module and give the same output as that of the actual product.
In Top-Down integration testing, the testing takes place from top to bottom, following the control flow or architectural structure. These stubs are the modules that act as a temporary replacement for a called module and give the same output as that of actual product.
Types of Stubs
- Displays a trace message.
- Display parameter values.
- Return a value from a table.
- Lastly return table value selected by parameter.
- The tested product is exceptionally predictable.
- When contrasted with the drivers, Stubs are easier to the creator.
- Through Top-Down integration, it is conceivable to acquire an early model.
- Checks real control or choice ahead of schedule in the test procedure.
- The essential usefulness of the product is tested toward the end of the cycle.
- It requires numerous stubs.
- Modules at the lower level tested insufficiently.
Its Advantages and Disadvantages
Advantages of Top Down Integration Testing
- Isolation of interface errors becomes easier because of incremental nature of top down integration.
- Test cases designed to test the integration of a module are reused during the regression tests performed after integrating other modules.
- Advantageous if major flaws occur toward the top of the program.
- It provides early working module of the program and so design defects can be found and corrected early.
Disadvantages of Top Down Integration Testing
- It may not be possible to observe meaningful system functions because of an absence of lower level modules and the presence of stubs.
- Test case selection and stub design become increasingly difficult when stubs lie far away from the top level module.
- Observation of test output is more difficult.
- Stubs will simulate setting of output parameters.
To Wrap Up
Associations around the globe are creating software and applications that significantly oblige these necessities. Thus, considering it is always good to evolve the software and test software in pieces.
Also, testers and developers are working tremendously hard. Hence, they are approving different testing systems that the developed software or product is without bug. Integration testing is one such sort of testing method, which tests the interfaces between the units or modules. Furthermore, it centers mainly on the interfaces and the stream of data between the modules. Consequently, to guarantee the quality and execution of the product, top down approach software testing is the most sensible kind of testing that should be actualized by testers everywhere throughout the world.