Unit testing incorporating hardware

Paul Boughton
The latest version of Tessy, the tool for automated module/unit/integration testing of embedded software, now enables to incorporate hardware in unit and integration testing.

The hardware under test either can be the on-chip peripherals of a microcontroller or hardware external to the microcontroller. This enables a so-called hardware-in-the-loop test for unit and integration testing. Such a test makes especially sense if the microcontroller is implemented as soft core in a FPGA, because in this case the on-chip peripherals actually are not hardware, but software, which might change during the course of the development and therefore needs repetitive testing. To accomplish such tests, special test hardware and software is used, which needs to be adapted to the test object in question.

Technically spoken, Tessy provides the ability to control the test hardware prior to a test. The test hardware is supplied by the user. It might be proprietary hardware or off-the-shelf hardware. The connection to Tessy is provided by a software adapter (a DLL). The interface of this adapter to Tessy is specified, the actual adapter software controlling the test hardware is implemented by the user. After each single test, Tessy determines the test results using this software adapter. The test results are values that are recorded during the test or determined after the test. Such data might need pre-processing by the adapter software.

The features of the test hardware, eg which signals are available and which of them are input respective output for the test object, are specified to Tessy using a configuration file in XML format. These specifications are specific to the test object and are provided by the user.

For more information,visit www.hitex.com/perm/tessy.html