They can call functions with supplied parameters and print out and compare the results to the desired value.
These individual objectives may be fulfilled by unit test framework tools, stubs or drivers.
[3] When attempting to build an application that needs to interface with an application on a mainframe computer, but no mainframe is available during development, a test harness may be built to use as a substitute this can mean that normally complex operations can be handled with a small amount of resources by providing pre-defined data and responses so the calculations performed by the mainframe are not needed.
It may be kept separate from the application source code and may be reused on multiple projects.
The test harness will generally be specific to a development environment such as Java.