feat(tests): add threading-lock test

This demonstrates how multiple threads can wait for the same lock and
get unblocked by priority, and within a prio by FIFO order.

Cargo.toml

@@ -18,6 +18,7 @@ members = [
   "tests/gpio",
   "tests/gpio-interrupt-nrf",
   "tests/gpio-interrupt-stm32",
+  "tests/threading-lock",
 ]
 
 exclude = ["src/lib"]

tests/laze.yml

@@ -3,3 +3,4 @@ subdirs:
   - gpio
   - gpio-interrupt-nrf
   - gpio-interrupt-stm32
+  - threading-lock

tests/threading-lock/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "threading-lock"
+version = "0.1.0"
+authors = ["Elena Frank <[email protected]>"]
+edition.workspace = true
+publish = false
+
+[dependencies]
+embassy-executor = { workspace = true }
+riot-rs = { path = "../../src/riot-rs", features = ["threading", "time"] }
+riot-rs-boards = { path = "../../src/riot-rs-boards" }
+portable-atomic = "1.6.0"

tests/threading-lock/laze.yml

@@ -0,0 +1,6 @@
+apps:
+  - name: threading-lock
+    selects:
+      - ?release
+      - executor-thread
+      - sw/threading

tests/threading-lock/src/main.rs

@@ -0,0 +1,72 @@
+#![no_main]
+#![no_std]
+#![feature(type_alias_impl_trait)]
+#![feature(used_with_arg)]
+
+use portable_atomic::{AtomicUsize, Ordering};
+use riot_rs::thread::{lock::Lock, thread_flags, ThreadId};
+
+static LOCK: Lock = Lock::new();
+static RUN_ORDER: AtomicUsize = AtomicUsize::new(0);
+static LOCK_ORDER: AtomicUsize = AtomicUsize::new(0);
+
+#[riot_rs::thread(autostart, priority = 1)]
+fn thread0() {
+    assert_eq!(RUN_ORDER.fetch_add(1, Ordering::AcqRel), 0);
+
+    LOCK.acquire();
+
+    // Unblock other threads in the order of their IDs.
+    //
+    // Because all other threads have higher priorities, setting
+    // a flag will each time cause a context switch and give each
+    // thread the chance to run and try acquire the lock.
+    thread_flags::set(ThreadId::new(1), 0b1);
+    thread_flags::set(ThreadId::new(2), 0b1);
+    thread_flags::set(ThreadId::new(3), 0b1);
+
+    assert_eq!(LOCK_ORDER.fetch_add(1, Ordering::AcqRel), 0);
+
+    LOCK.release();
+
+    // Wait for other threads to complete.
+    thread_flags::wait_all(0b111);
+    riot_rs::debug::log::info!("Test passed!");
+}
+
+#[riot_rs::thread(autostart, priority = 2)]
+fn thread1() {
+    thread_flags::wait_one(0b1);
+    assert_eq!(RUN_ORDER.fetch_add(1, Ordering::AcqRel), 1);
+
+    LOCK.acquire();
+    assert_eq!(LOCK_ORDER.fetch_add(1, Ordering::AcqRel), 2);
+    LOCK.release();
+
+    thread_flags::set(ThreadId::new(0), 0b1);
+}
+
+#[riot_rs::thread(autostart, priority = 3)]
+fn thread2() {
+    thread_flags::wait_one(0b1);
+    assert_eq!(RUN_ORDER.fetch_add(1, Ordering::AcqRel), 2);
+
+    LOCK.acquire();
+    // Expect to be the second thread that acquires the lock.
+    assert_eq!(LOCK_ORDER.fetch_add(1, Ordering::AcqRel), 1);
+    LOCK.release();
+
+    thread_flags::set(ThreadId::new(0), 0b10);
+}
+
+#[riot_rs::thread(autostart, priority = 2)]
+fn thread3() {
+    thread_flags::wait_one(0b1);
+    assert_eq!(RUN_ORDER.fetch_add(1, Ordering::AcqRel), 3);
+
+    LOCK.acquire();
+    assert_eq!(LOCK_ORDER.fetch_add(1, Ordering::AcqRel), 3);
+    LOCK.release();
+
+    thread_flags::set(ThreadId::new(0), 0b100);
+}