Measuring and Validating Response Time in Real-time Systems

To measure and validate response time in real-time systems, use the following macros:

Name	Details
`CppTest_Time` `CppTest_TimeInit(CPPTEST_INTEGER seconds, CPPTEST_INTEGER nanoseconds);`	Initializes the `CppTest_Time` structure with the given values. Nanoseconds should be between -999999999 and 999999999
`CppTest_Time CppTest_TimeCurrent();`	Initializes the `CppTest_Time` structure with the current time. Time is stored as number of seconds (and nanoseconds) since 00:00:00 UTC, January 1, 1970. Accuracy depends on platform used.
`CppTest_Time` `CppTest_TimeDiff(CppTest_Time t1, CppTest_Time t2);`	Returns the difference between `t1` and `t2`.
`int CppTest_TimeCompare(CppTest_Time t1, CppTest_Time t2);`	Compares two `CppTest_Time` structures. Returns: < 0: If `t1` is smaller/earlier than `t2` == 0: If `t1` and `t2` are equal > 0: If `t1` is bigger/later than `t2`

Here is an example of how to use these macros to measure and report time:

   ...
   /* Collect start time */
   CppTest_Time start = CppTest_TimeCurrent();
   /* Tested function call */
   int _return  = ::foo();
   /* Compute time diff */
   CppTest_Time stop = CppTest_TimeCurrent();
   CppTest_Time diff = CppTest_TimeDiff(stop, start);
   /* Report time diff (assuming positive values) */
   CPPTEST_MESSAGE(cpptestFormat("Call time for foo(): %d.%09d", diff.seconds, diff.nanoseconds));
   ...

Here is an example of how to use these macros to check and compare time:

   ...
   /* Verify execution time */
   CppTest_Time limit5ms = CppTest_TimeInit(0, 5000000);    
   CPPTEST_ASSERT(CppTest_TimeCompare(diff, limit5ms) < 0)    
   ...

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Measuring and Validating Response Time in Real-time Systems