embassy/embassy-time/src/driver_mock.rs
2024-12-22 21:00:23 +01:00

146 lines
3.8 KiB
Rust

use core::cell::RefCell;
use core::task::Waker;
use critical_section::Mutex as CsMutex;
use embassy_time_driver::Driver;
use embassy_time_queue_utils::Queue;
use crate::{Duration, Instant};
/// A mock driver that can be manually advanced.
/// This is useful for testing code that works with [`Instant`] and [`Duration`].
///
/// This driver can also be used to test runtime functionality, such as
/// timers, delays, etc.
///
/// # Example
///
/// ```ignore
/// fn has_a_second_passed(reference: Instant) -> bool {
/// Instant::now().duration_since(reference) >= Duration::from_secs(1)
/// }
///
/// fn test_second_passed() {
/// let driver = embassy_time::MockDriver::get();
/// let reference = Instant::now();
/// assert_eq!(false, has_a_second_passed(reference));
/// driver.advance(Duration::from_secs(1));
/// assert_eq!(true, has_a_second_passed(reference));
/// }
/// ```
pub struct MockDriver(CsMutex<RefCell<InnerMockDriver>>);
embassy_time_driver::time_driver_impl!(static DRIVER: MockDriver = MockDriver::new());
impl MockDriver {
/// Creates a new mock driver.
pub const fn new() -> Self {
Self(CsMutex::new(RefCell::new(InnerMockDriver::new())))
}
/// Gets a reference to the global mock driver.
pub fn get() -> &'static MockDriver {
&DRIVER
}
/// Resets the internal state of the mock driver
/// This will clear and deallocate all alarms, and reset the current time to 0.
pub fn reset(&self) {
critical_section::with(|cs| {
self.0.borrow(cs).replace(InnerMockDriver::new());
});
}
/// Advances the time by the specified [`Duration`].
/// Calling any alarm callbacks that are due.
pub fn advance(&self, duration: Duration) {
critical_section::with(|cs| {
let inner = &mut *self.0.borrow_ref_mut(cs);
inner.now += duration;
// wake expired tasks.
inner.queue.next_expiration(inner.now.as_ticks());
})
}
}
impl Driver for MockDriver {
fn now(&self) -> u64 {
critical_section::with(|cs| self.0.borrow_ref(cs).now).as_ticks()
}
fn schedule_wake(&self, at: u64, waker: &Waker) {
critical_section::with(|cs| {
let inner = &mut *self.0.borrow_ref_mut(cs);
// enqueue it
inner.queue.schedule_wake(at, waker);
// wake it if it's in the past.
inner.queue.next_expiration(inner.now.as_ticks());
})
}
}
struct InnerMockDriver {
now: Instant,
queue: Queue,
}
impl InnerMockDriver {
const fn new() -> Self {
Self {
now: Instant::from_ticks(0),
queue: Queue::new(),
}
}
}
#[cfg(test)]
mod tests {
use core::sync::atomic::{AtomicBool, Ordering};
use std::sync::Arc;
use std::task::Wake;
use serial_test::serial;
use super::*;
fn setup() {
DRIVER.reset();
}
#[test]
#[serial]
fn test_advance() {
setup();
let driver = MockDriver::get();
let reference = driver.now();
driver.advance(Duration::from_secs(1));
assert_eq!(Duration::from_secs(1).as_ticks(), driver.now() - reference);
}
#[test]
#[serial]
fn test_schedule_wake() {
setup();
static CALLBACK_CALLED: AtomicBool = AtomicBool::new(false);
struct MockWaker;
impl Wake for MockWaker {
fn wake(self: Arc<Self>) {
CALLBACK_CALLED.store(true, Ordering::Relaxed);
}
}
let waker = Arc::new(MockWaker).into();
let driver = MockDriver::get();
driver.schedule_wake(driver.now() + 1, &waker);
assert_eq!(false, CALLBACK_CALLED.load(Ordering::Relaxed));
driver.advance(Duration::from_secs(1));
assert_eq!(true, CALLBACK_CALLED.load(Ordering::Relaxed));
}
}