What is a test driver in software testing?

Answer 1

Test Driver or stubs are used for integration testing. So you have 3 modules say A, B and C in your application. The A and C is ready but the bridge between A to C is B is not ready so how you can test the whole system A, B and C together. Here you need to use some dummy system which would take the input and pass it to C. It is not the complete B system but still will serve the purpose to have a path between A and C. This is called stub and driver.

Answer 2

While integrating sub-modules in Bottom-Up approach, if at all a mandatory module is missing then that missing module will be replaced by a temporary program. This program is called Driver in Software Testing. Drivers are used during Bottom-up integration testing in order to simulate the behaviour of the upper level modules that are not yet integrated.Drivers are the modules that act as temporary replacement for a calling module and give the same output as that of the actual product.

Drivers are also used when the software needs to interact with an external system and are usually complex than stubs.