In the context of automated testing, it is very important to reuse a fragment of code to exercise a certain operation. However, the ways it is reused are quite diversified.
For instance, an installer is used to set up an application under tests. At the same time, it is also a software component to be tested with various sets of its parameters. In order to detect bugs triggered by combinations of installation-time parameters and runtime parameters, you may need to run it with different parameters but as a part of set up procedure, not a procedure to be examined under tests.
Note that the parameters I mentioned above is "test parameters". Not merely ones directly defined as input of the installer, but also, ones defined by test practitioners, and it may mean "how" the practitioner uses the target component. For instance "UI to access the component" can be one test parameter and its values can be like "GUI", "CLI", etc.