Use Stubs And Drivers?

Stubs are dummy modules that are always distinguish as "called programs", or you can say that is handle in integration testing (top down approach), it used when sub programs are under construction.

Stubs are considered as the dummy modules that always simulate the low level modules.

Drivers are also considered as the form of dummy modules which are always distinguished as "calling programs”, that is handled in bottom up integration testing, it is only used when main programs are under construction.

Drivers are considered as the dummy modules that always simulate the high level modules.

Example of Stubs and Drivers is given below:-

For Example we have 3 modules login, home, and user module. Login module is ready and need to test it, but we call functions from home and user (which is not ready). To test at a selective module we write a short dummy piece of a code which simulates home and user, which will return values for Login, this piece of dummy code is always called Stubs and it is used in a top down integration.  

Considering the same Example above: If we have Home and User modules get ready and Login module is not ready, and we need to test Home and User modules Which return values from Login module, So to extract the values from Login module We write a Short Piece of Dummy code for login which returns value for home and user, So these pieces of code is always called Drivers and it is used in Bottom Up Integration

Conclusion:-

So it is fine from the above example that Stubs act “called” functions in top down integration.Drivers are “calling” Functions in bottom up integration.

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The concept of Stubs and Drivers are mostly used in the case of component testing. Component testing may be done in isolation with the rest of the system depending upon the context of the development cycle.

Stubs and drivers are used to replace the missing software and simulate the interface between the software components in a simple manner.

Suppose you have a function (Function A) that calculates the total marks obtained by a student in a particular academic year. Suppose this function derives its values from another function (Function b) which calculates the marks obtained in a particular subject.

You have finished working on Function A and wants to test it. But the problem you face here is that you can't seem to run the Function A without input from Function B; Function B is still under development. In this case, you create a dummy function to act in place of Function B to test your function. This dummy function gets called by another function. Such a dummy is called a Stub.

To understand what a driver is, suppose you have finished Function B and is waiting for Function A to be developed. In this case you create a dummy to call the Function B. This dummy is called the driver.