Editing Avionics software (section)

===Black box and acceptance testing===
Meanwhile, the test engineers usually begin assembling a test rig, and releasing preliminary tests for use by the software engineers.  At some point, the tests cover all of the functions of the engineering specification.  At this point, testing of the entire avionic unit begins.  The object of the acceptance testing is to prove that the unit is safe and reliable in operation.

The first test of the software, and one of the most difficult to meet in a tight schedule, is a realistic test of the unit's radio emissions.  This usually must be started early in the project to assure that there is time to make any necessary changes to the design of the electronics.
The software is also subjected to a structural coverage analysis, where tests are run and code coverage is collected and analyzed.