2 Why We Need Model-Based Testing

Overview 45
?Message ’100.0’, Message, OK
CheckMessage ’100.0’, compare to 99.9, OK
In this run, OutOfRangeMessageWhenIdle, the controller carries out a calibrate command
using an out-of-range temperature value. The message carrying this value was
late; it arrived after the time-out expired, and was not checked.
?Timeout, Timeout, Error
Reset
?Message ’99.9’, Message, Error
CheckMessage ’99.9’, compare to 99.9, OK
?Timeout, Timeout, OK
Poll
?Timeout, Message, OK
ReportLostMessage
?Message ’999.9’, Timeout, OK
?Command, Timeout, OK
Calibrate ’999.9’
In this run, LostMessageWhenIdle, the controller reaches a deadlocks. The sensor
does not reply to the initial reset command. The controller does not restart the timer;
polling never begins. The sensor status never becomes OK, so calibrate commands
are never carried out.
?Timeout, Timeout, Error
Reset
?Timeout, Message, Error
?Command, Message, Error
?Command, Message, Error
In this run, InitialOutOfRangeMessage, the controller cycles without making
progress. It keeps sending reset commands but the sensor status never becomes
OK. The first message in response to the initial reset command is out-of-range, so
subsequent within-range messages are never accepted, and the calibrate command
can never be carried out.
?Timeout, Timeout, Error
Reset
?Message ’999.9’, Message, Error
CheckMessage ’999.9’, compare to 999.9, OK
?Timeout, Timeout, OK
Poll
?Message ’99.9’, Message, OK
more free ebooks download links at:
http://www.ebook-x.com