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|
use core::cell::RefCell;
use critical_section::Mutex as CsMutex;
use embassy_time_driver::{AlarmHandle, Driver};
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) {
let notify = {
critical_section::with(|cs| {
let mut inner = self.0.borrow_ref_mut(cs);
inner.now += duration;
let now = inner.now.as_ticks();
inner
.alarm
.as_mut()
.filter(|alarm| alarm.timestamp <= now)
.map(|alarm| {
alarm.timestamp = u64::MAX;
(alarm.callback, alarm.ctx)
})
})
};
if let Some((callback, ctx)) = notify {
(callback)(ctx);
}
}
}
impl Driver for MockDriver {
fn now(&self) -> u64 {
critical_section::with(|cs| self.0.borrow_ref(cs).now).as_ticks()
}
unsafe fn allocate_alarm(&self) -> Option<AlarmHandle> {
critical_section::with(|cs| {
let mut inner = self.0.borrow_ref_mut(cs);
if inner.alarm.is_some() {
None
} else {
inner.alarm.replace(AlarmState::new());
Some(AlarmHandle::new(0))
}
})
}
fn set_alarm_callback(&self, _alarm: AlarmHandle, callback: fn(*mut ()), ctx: *mut ()) {
critical_section::with(|cs| {
let mut inner = self.0.borrow_ref_mut(cs);
let Some(alarm) = inner.alarm.as_mut() else {
panic!("Alarm not allocated");
};
alarm.callback = callback;
alarm.ctx = ctx;
});
}
fn set_alarm(&self, _alarm: AlarmHandle, timestamp: u64) -> bool {
critical_section::with(|cs| {
let mut inner = self.0.borrow_ref_mut(cs);
if timestamp <= inner.now.as_ticks() {
false
} else {
let Some(alarm) = inner.alarm.as_mut() else {
panic!("Alarm not allocated");
};
alarm.timestamp = timestamp;
true
}
})
}
}
struct InnerMockDriver {
now: Instant,
alarm: Option<AlarmState>,
}
impl InnerMockDriver {
const fn new() -> Self {
Self {
now: Instant::from_ticks(0),
alarm: None,
}
}
}
struct AlarmState {
timestamp: u64,
callback: fn(*mut ()),
ctx: *mut (),
}
impl AlarmState {
const fn new() -> Self {
Self {
timestamp: u64::MAX,
callback: Self::noop,
ctx: core::ptr::null_mut(),
}
}
fn noop(_ctx: *mut ()) {}
}
unsafe impl Send for AlarmState {}
#[cfg(test)]
mod tests {
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_set_alarm_not_in_future() {
setup();
let driver = MockDriver::get();
let alarm = unsafe { AlarmHandle::new(0) };
assert_eq!(false, driver.set_alarm(alarm, driver.now()));
}
#[test]
#[serial]
fn test_alarm() {
setup();
let driver = MockDriver::get();
let alarm = unsafe { driver.allocate_alarm() }.expect("No alarms available");
static mut CALLBACK_CALLED: bool = false;
let ctx = &mut () as *mut ();
driver.set_alarm_callback(alarm, |_| unsafe { CALLBACK_CALLED = true }, ctx);
driver.set_alarm(alarm, driver.now() + 1);
assert_eq!(false, unsafe { CALLBACK_CALLED });
driver.advance(Duration::from_secs(1));
assert_eq!(true, unsafe { CALLBACK_CALLED });
}
#[test]
#[serial]
fn test_allocate_alarm() {
setup();
let driver = MockDriver::get();
assert!(unsafe { driver.allocate_alarm() }.is_some());
assert!(unsafe { driver.allocate_alarm() }.is_none());
}
}
|
