802.15.4 raw stack driver tests

Two things are worth noticing:
1. I discovered that due to a flaw in ring buffer design,
   only N-1 slots are usable there. This is space-inefficient.
2. In order to inject upcalls at a small moment between subscribing
   to the RECEIVED_FRAME upcall and calling yield_wait, a hacky way
   is employed with custom FakeSyscalls implementation.
   Such upcall injection is necessary, because:
   - before subscription, scheduling an upcall is a no-op;
   - if we don't schedule an upcall before yield_wait, the test
     framework purposefully panics to prevent deadlock.

apis/net/ieee802154/src/tests.rs

@@ -0,0 +1,272 @@
+use libtock_platform::{RawSyscalls, Register};
+use libtock_unittest::fake::{self, ieee802154::Frame as FakeFrame, Ieee802154Phy};
+
+/// The Ieee8021514Phy userspace driver calls yield_wait() immediately after subscribe().
+/// Normally, it would wait for the kernel to receive a frame and then asynchronously
+/// schedule an upcall, but in this testing framework it is required to schedule
+/// an upcall before yield_wait(), because otherwise a panic is raised.
+///
+/// HACK: This wraps around fake::Syscalls to hook subscribe::FRAME_RECEIVED
+/// so that immediately after subscribing for the upcall, frames are received
+/// by the kernel driver and the corresponding upcall is scheduled.
+struct FakeSyscalls;
+
+unsafe impl RawSyscalls for FakeSyscalls {
+    unsafe fn yield1([r0]: [Register; 1]) {
+        libtock_unittest::fake::Syscalls::yield1([r0])
+    }
+
+    unsafe fn yield2([r0, r1]: [Register; 2]) {
+        libtock_unittest::fake::Syscalls::yield2([r0, r1])
+    }
+
+    unsafe fn syscall1<const CLASS: usize>([r0]: [Register; 1]) -> [Register; 2] {
+        libtock_unittest::fake::Syscalls::syscall1::<CLASS>([r0])
+    }
+
+    unsafe fn syscall2<const CLASS: usize>([r0, r1]: [Register; 2]) -> [Register; 2] {
+        libtock_unittest::fake::Syscalls::syscall2::<CLASS>([r0, r1])
+    }
+
+    unsafe fn syscall4<const CLASS: usize>([r0, r1, r2, r3]: [Register; 4]) -> [Register; 4] {
+        let trigger_rx_upcall = match CLASS {
+            libtock_platform::syscall_class::SUBSCRIBE => {
+                let driver_num: u32 = r0.try_into().unwrap();
+                let subscribe_num: u32 = r1.try_into().unwrap();
+                let len: usize = r3.into();
+                assert_eq!(driver_num, DRIVER_NUM);
+
+                subscribe_num == subscribe::FRAME_RECEIVED && len > 0
+            }
+            _ => false,
+        };
+
+        let ret = libtock_unittest::fake::Syscalls::syscall4::<CLASS>([r0, r1, r2, r3]);
+        if trigger_rx_upcall {
+            if let Some(driver) = Ieee802154Phy::instance() {
+                driver.driver_receive_pending_frames();
+
+                if driver.has_pending_rx_frames() {
+                    driver.trigger_rx_upcall();
+                }
+            }
+        }
+        ret
+    }
+}
+
+use crate::{subscribe, DRIVER_NUM};
+
+use super::{RxOperator, RxRingBuffer};
+
+type Ieee802154 = super::Ieee802154<FakeSyscalls>;
+type RxSingleBufferOperator<'buf, const N: usize> =
+    super::RxSingleBufferOperator<'buf, N, FakeSyscalls>;
+
+#[test]
+fn no_driver() {
+    let _kernel = fake::Kernel::new();
+    assert!(!Ieee802154::exists());
+}
+
+#[test]
+fn exists() {
+    let kernel = fake::Kernel::new();
+    let driver = fake::Ieee802154Phy::new();
+    kernel.add_driver(&driver);
+
+    assert!(Ieee802154::exists());
+}
+
+#[test]
+fn configure() {
+    let kernel = fake::Kernel::new();
+    let driver = fake::Ieee802154Phy::new();
+    kernel.add_driver(&driver);
+
+    let pan: u16 = 0xcafe;
+    let addr_short: u16 = 0xdead;
+    let addr_long: u64 = 0xdeaddad;
+    let tx_power: i8 = -0x42;
+    let channel: u8 = 0xff;
+
+    Ieee802154::set_pan(pan);
+    Ieee802154::set_address_short(addr_short);
+    Ieee802154::set_address_long(addr_long);
+    Ieee802154::set_tx_power(tx_power).unwrap();
+    Ieee802154::set_channel(channel).unwrap();
+
+    Ieee802154::commit_config();
+
+    assert_eq!(Ieee802154::get_pan().unwrap(), pan);
+    assert_eq!(Ieee802154::get_address_short().unwrap(), addr_short);
+    assert_eq!(Ieee802154::get_address_long().unwrap(), addr_long);
+    assert_eq!(Ieee802154::get_channel().unwrap(), channel);
+    assert_eq!(Ieee802154::get_tx_power().unwrap(), tx_power);
+}
+
+#[test]
+fn transmit_frame() {
+    let kernel = fake::Kernel::new();
+    let driver = fake::Ieee802154Phy::new();
+    kernel.add_driver(&driver);
+
+    Ieee802154::transmit_frame(b"foo").unwrap();
+    Ieee802154::transmit_frame(b"bar").unwrap();
+    assert_eq!(
+        driver.take_transmitted_frames(),
+        &[&b"foo"[..], &b"bar"[..]],
+    );
+}
+
+mod rx {
+    use super::*;
+    fn test_with_driver(test: impl FnOnce(&Ieee802154Phy)) {
+        let kernel = fake::Kernel::new();
+        let driver = fake::Ieee802154Phy::new();
+        kernel.add_driver(&driver);
+
+        test(&driver)
+    }
+
+    fn test_with_single_buf_operator<const SUPPORTED_FRAMES: usize>(
+        driver: &Ieee802154Phy,
+        test: impl Fn(&Ieee802154Phy, &mut dyn RxOperator),
+    ) {
+        let mut buf = RxRingBuffer::<SUPPORTED_FRAMES>::new();
+        let mut operator = RxSingleBufferOperator::new(&mut buf);
+
+        test(driver, &mut operator)
+    }
+
+    fn no_frame_comes(_driver: &Ieee802154Phy, operator: &mut dyn RxOperator) {
+        // No frame is available, so we expect to panic in tests,
+        // because yield_wait is called without pending upcalls.
+        // THIS PANICS
+        let _ = operator.receive_frame();
+    }
+
+    #[test]
+    #[should_panic = "yield-wait called with no queued upcall"]
+    fn no_frame_comes_single_buf() {
+        test_with_driver(|driver| {
+            const SUPPORTED_FRAMES: usize = 2;
+
+            test_with_single_buf_operator::<SUPPORTED_FRAMES>(driver, no_frame_comes);
+        });
+    }
+
+    #[test]
+    fn receive_frame() {
+        test_with_driver(|driver| {
+            const SUPPORTED_FRAMES: usize = 2;
+
+            test_with_single_buf_operator::<SUPPORTED_FRAMES>(driver, |driver, operator| {
+                let frame1 = b"alamakota";
+
+                driver.radio_receive_frame(FakeFrame::with_body(frame1));
+                // Now one frame is available.
+
+                let got_frame1 = operator.receive_frame().unwrap();
+                assert_eq!(got_frame1.payload_len as usize, frame1.len());
+                assert_eq!(
+                    &got_frame1.body[..got_frame1.payload_len as usize],
+                    &frame1[..]
+                );
+            });
+        });
+    }
+
+    fn only_one_frame_comes(driver: &Ieee802154Phy, operator: &mut dyn RxOperator) {
+        let frame1 = b"alamakota";
+
+        // Now one frame is available.
+        driver.radio_receive_frame(FakeFrame::with_body(frame1));
+        let got_frame1 = operator.receive_frame().unwrap();
+        assert_eq!(got_frame1.payload_len as usize, frame1.len());
+        assert_eq!(&got_frame1.body[..frame1.len()], frame1);
+
+        // But only one!
+        // THIS PANICS
+        let _ = operator.receive_frame();
+    }
+
+    #[test]
+    #[should_panic = "yield-wait called with no queued upcall"]
+    fn receive_frame_only_one_single_buf() {
+        test_with_driver(|driver| {
+            const SUPPORTED_FRAMES: usize = 2;
+
+            test_with_single_buf_operator::<SUPPORTED_FRAMES>(driver, only_one_frame_comes);
+        });
+    }
+
+    #[test]
+    fn receive_many_frames() {
+        test_with_driver(|driver| {
+            const SUPPORTED_FRAMES: usize = 3;
+
+            test_with_single_buf_operator::<{ SUPPORTED_FRAMES + 1 }>(
+                driver,
+                |driver, operator| {
+                    for (times, frame) in
+                        [1, 2, 3, 10]
+                            .iter()
+                            .copied()
+                            .zip([&b"one"[..], b"two", b"three", b"ten"])
+                    {
+                        for _ in 0..times {
+                            driver.radio_receive_frame(FakeFrame::with_body(frame));
+                        }
+
+                        for _ in 0..core::cmp::min(times, SUPPORTED_FRAMES) {
+                            let got_frame = operator.receive_frame().unwrap();
+                            let expected_frame = frame;
+                            assert_eq!(got_frame.payload_len as usize, expected_frame.len());
+                            assert_eq!(
+                                &got_frame.body[..got_frame.payload_len as usize],
+                                expected_frame
+                            );
+                        }
+                    }
+                },
+            );
+        });
+    }
+
+    #[test]
+    fn receive_various_frames() {
+        test_with_driver(|driver| {
+            const SUPPORTED_FRAMES: usize = 3;
+
+            test_with_single_buf_operator::<{ SUPPORTED_FRAMES + 1 }>(
+                driver,
+                |driver, operator| {
+                    let frame1 = b"alamakota";
+                    let frame2 = b"ewamamewe";
+                    let frame3 = b"wojciechmalaptop";
+                    let frames: [&[u8]; 3] = [frame1, frame2, frame3];
+
+                    let order = [0, 1, 2, 2, 1, 0, 2, 2, 1, 0, 2];
+                    for idx in order {
+                        let times = idx + 1;
+
+                        for _ in 0..times {
+                            driver.radio_receive_frame(FakeFrame::with_body(frames[idx]));
+                        }
+
+                        for _ in 0..core::cmp::min(times, SUPPORTED_FRAMES) {
+                            let got_frame = operator.receive_frame().unwrap();
+                            let expected_frame = frames[idx];
+                            assert_eq!(got_frame.payload_len as usize, expected_frame.len());
+                            assert_eq!(
+                                &got_frame.body[..got_frame.payload_len as usize],
+                                expected_frame
+                            );
+                        }
+                    }
+                },
+            );
+        });
+    }
+}