Unit testing consists of testing the functions, procedures or methods that a source module makes available to the rest of the application. A “unit” may be anything from a single function to an entire library. The essential point of unit testing is that only a small part of the application is tested.

Usually, the easiest way to do this is to write a small application, called a “driver” or “test harness”, that exercises these exposed functions and reports the results. The driver or harness is normally written with the same development tool as the unit under test. The test harness must have the same access to the unit programming interface (for example, header in C++, Interface part in Delphi) as all of the other units in the final application.

At a minimum, any automated testing tool should provide a way to --

TestComplete does all of these conveniently. The Stores function keeps most forms of output as standards for later comparison, which you can accomplish using TestComplete’s built-in methods.

The fact that TestComplete can access internal objects, methods and properties of the application under test, gives you the ability to put the test harness methods in TestComplete scripts, or in the tested application itself. In order for TestComplete to access internal objects, methods and properties of an application, this application must be compiled as an Open Application. Also, there are some language-specific requirements that your application's methods and properties must meet if you want to access them from the TestComplete unit testing code.

TestComplete supports MSTest, JUnit, NUnit, DUnit and TCUnitTest unit test types.

TCUnitTest tests are unit tests that are performed by TestComplete itself (to learn how TestComplete can access the testing application’s internals, see above). Once you have specified the application to be tested, you can visually configure which methods you want to call and in which order to call them.

MSTest, JUnit, NUnit and DUnit tests are performed by the corresponding unit testing tool (MSTest, JUnit, NUnit or DUnit), not by TestComplete. TestComplete lets you visually customize which tests to run and with which parameters. TestComplete projects let you coordinate all of your test types with one interface.

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