Test harnesses is the important components in software testing, especially in the context of unit testing, integration testing, and system testing. They are used to simulate various parts of the system under test (SUT) to ensure that software components function correctly in isolation or in combination.
Test Harness:
A test harness is a collection of software and test data configured to test a program unit by running it under different conditions (such as different inputs or interactions). It consists of test scripts, drivers, stubs, and various tools to automate the testing process. Test harnesses are often used in unit testing, integration testing, and regression testing.
Components of a Test Harness:
- Test Drivers: Software components used to invoke methods/functions of the module being tested (often called the unit under test or UUT).
- Test Stubs: Used to simulate modules or systems that a particular module interacts with but which are not yet implemented or are too complex to include in the test.
- Test Data: Input values or conditions used to test the software.
- Automation Scripts: Scripts that automate the testing process, capturing inputs, executing the test cases, and reporting results.
- Test Execution Engine: The mechanism that runs test cases, manages the sequence, and records results.
Purpose of a Test Harness:
- Automates the testing process, allowing tests to be run frequently and systematically.
- Enables testing in isolation (e.g., when certain dependencies of the system are not ready or available).
- Facilitates regression testing by allowing previously executed tests to be run automatically after each change in code.
- Allows the simulation of different inputs and outputs to ensure comprehensive testing.