This commit fixes a frequent unit test flake in ot-test-trickle_timer
under the TestTrickleTimerMinMaxIntervalChange test case.
The test case starts the trickle timer with Imin = 2000 and
Imax = 2000. The random time t (mTimeInInterval) is chosen in
[1000, 2000), so t can range up to 1999.
When t randomly evaluates to 1999, t + 1 becomes 2000. Calling
timer.SetIntervalMax(2000) triggers an early-exit optimization
in TrickleTimer::SetIntervalMax because mIntervalMax is already 2000,
leaving the scheduled timer's fire time unchanged. The test then
crashes on the assertion expecting the fire time to have changed.
This is resolved by setting the new interval max to
Min(t + 1, interval - 1). This ensures that the requested value is
strictly less than 2000 even when t = 1999, successfully triggering
the interval shortening and rescheduling logic tested by this case.
This commit updates unit test modules to be defined under the `ot`
namespace. This aligns all the unit tests to follow the same
model, eliminating the need to use `ot::` prefix in unit test
code.
This commit moves the `instance` module to a newly added folder
`core/instance` (from `core/common`. Header file `extension.hpp`
and its example is also moved to the same folder.
This commit updates the `TrickleTimer` to allow `IntervalMax` and
`IntervalMin` to be changed while the timer is running. In particular,
when `IntervalMax` is changed to a value that is shorter than the
current interval being used by the timer, the timer will adapt the
new shorter interval and may fire immediately.
A unit test `test_trickle_timer` has been added to validate the
behavior of `TrickleTimer` in detail. All different scenarios where
`IntervalMax` or `IntervalMin` are changed are covered by the
unit test.
The new mechanism to change the trickle timer `IntervalMax` is
used to update the MLE Advertisement trickle timer. The `IntervalMax`
is determined based on the number of router neighbors of the device
with link quality 2 or better. If the device has fewer router neighbors,
it will use a shorter `IntervalMax`. As new links are established
with routers, the `IntervalMax` is recalculated and updated on the
Advertisement trickle timer.
This commit also adds a new test `test-024-mle-adv-imax-change.py` to
validate updates to the `IntervalMax` value based on the number of
router neighbors.
Co-authored-by: David Smith <david.smith@mmbnetworks.com>
Jonathan Hui