Lecture Notes in Computer Science 3472

16 TTCN-3 479
To apply a sending operation (stimuli) there shall be specified a port used to
send the data, the value to be transmitted, and optionally an address to identify
a particular connection if the port is connected to many ports. Additionally, at
procedure based communication the response and error operation are needed;
they are specified by using the getreply and catch operations.
These operations are
• send: send a message to SUT,
• call: to invoke a remote procedure,
• reply: to reply a value when an own procedure is called,
• raise: to report an exception when an own procedure is called an something
is wrong in the procedure call.
The message based communication is asynchronous communication. The
sending operations are non-blocking; after sending the data, the system does
not wait for response. The receive operations block the execution until a matching
value is received.
A receiving operation specifies a port at which the operation takes place,
defines a matching part for selection of valid receiving values and optionally
specifies an address to identify the connection (if the port is connected to many
ports).
These operations are
• receive: receive a message from SUT
• getreply: specifies that a method is invoked
• trigger: specifies a message that shall receive in order to go to the next
statements
• catch: to collect an exception reported at remote procedure invocation.
Timer Operations The behavior specification may use timers. A timer is used
as a type; therefore instances of it can be declared. The operations with timers
are start, stop, read (to read the elapsed time), running (to check if the timer
is running) and timeout (to check if timeout event occurred). At the declaration
of a timer, a value can be assigned; the value is of type float. The start command
may be used with parameter (the duration for which the timer will be running)
or without parameter (when the default value specified at declaration is used).
In our example, we define a timer on PTCType component and use it in the
SeparateSearchFunctional behavior. In general, timers are used to measure
the time between sending a stimuli and the SUT’s response. If the SUT’s answer
does not come in a predefined period of time, usually the verdict is set to fail.
Verdict Handling The verdicts can be set and retrieved by using the setverdict
and getverdict operations respectively. These operations are allowed in test
cases, functions and altsteps. For verdict declaration and instantiation, TTCN-3
provides the verdicttype type. This type is an enumeration of five values: pass,
fail, inconc, none and error.