Require explicit seeds for `Simulation` and `SimulatedEnvironment` to
ensure reproducible test results.
Also:
- Drop packets in `FakeUdpSocket` when the receive queue is full to
prevent unbounded memory growth during stress tests.
- Improve synchronization in `Simulation::run_until` by adding a timeout
to the barrier wait, preventing hangs if a runner is unregistered.
Introduces a new testing support library 'testing/support' that provides
a clean, modular, and fully deterministic environment for testing
toxcore components.
These are more convenient and safer than the manual vtables we have in
the fuzzer support code. We can override individual member functions,
and C++ will take care of correctly casting and offsetting this-pointers
when needed.
* Use-after-free because we free network before dht in one case.
* Various unchecked allocs in tests (not so important).
* We used to not check whether ping arrays were actually allocated in DHT.
* `ping_kill` and `ping_array_kill` used to crash when passing NULL.
Also:
* Added an assert in all public API functions to ensure tox isn't NULL.
The error message you get from that is a bit nicer than "Segmentation
fault" when clients (or our tests) do things wrong.
* Decreased the sleep time in iterate_all_wait from 20ms to 5ms.
Everything seems to still work with 5ms, and this greatly decreases
the amount of time spent per test run, making oomer run much faster.
