What is "test harness"

n. (context computing English) A software framework containing tests to verify the behaviour of other software components.

In software testing, a test harness or automated test framework is a collection of software and test data configured to test a program unit by running it under varying conditions and monitoring its behavior and outputs. It has two main parts: the test execution engine and the test script repository.

Test harnesses allow for the automation of tests. They can call functions with supplied parameters and print out and compare the results to the desired value. The test harness is a hook to the developed code, which can be tested using an automation framework.

A test harness should allow specific tests to run (this helps in optimizing), orchestrate a runtime environment, and provide a capability to analyse results.

The typical objectives of a test harness is to:

• Automate the testing process.
• Execute test suites of test cases.
• Generate associated test reports.

These individual objectives may be fulfilled by unit test framework tools, stubs or drivers.

A test harness may provide some of the following benefits:

• Increased productivity due to automation of the testing process.
• Increased probability that regression testing will occur.
• Increased quality of software components and application.
• Repeatability of subsequent test runs.
• Offline testing (e.g. at times that the office is not staffed, like overnight).
• Access to conditions and/or use cases that are otherwise difficult to simulate (load, for example).