To run a test at a set rate, you add a loop to the schedule to
control the iteration rate, and then add tests to the loop. The tests, which
are children of the loop, are controlled by the loop. If the loop contains
a synchronization point, the synchronization point is released after the first
iteration of the loop and stays released for all further iterations.
About this task
To add a loop that controls the iteration rate for running tests:
Procedure
- In the Test Navigator, browse to the schedule and double-click
it. The schedule opens.
- Click the element that will be the parent of the loop, and then
click .
- In the Schedule Element Details area, type
the number of iterations that the loop will repeat.
- Select Control the rate of iteration. Selecting this field maintains a set transaction rate for all schedule
items that are children of this loop.
- At Iteration rate, type a number and select
a time unit. This sets the actual rate.
- Select or clear the Randomly vary the delay between
iterations check box. Selecting this check box causes the delay
to vary slightly. This option models your users more accurately because rather
than delaying iterations at fixed intervals, the delay amounts are varied
randomly while maintaining the same average iteration rate.
Note: Statistically, the Randomly
vary the delay between iterations option sets delay amounts
at random from a negative exponential distribution with the same mean
as the fixed delay value. The negative exponential distribution has
a long "tail," which means that a very small number of delays will
have very large values. Therefore, make sure that the application
you are testing is not negatively affected by long periods of inactivity
(such as a timeout that disconnects the user).
- Select or clear the Delay before the first iteration
of the loop check box. Selecting this check box staggers the first
delay in each iteration, so that you get a realistic mix at the first iteration.
What to do next
After you have added the loop, you add the schedule items, usually
tests, that the loop controls.