test(test_suite): add another test for Task::set_priority

Author: yvt

src/constance_test_suite/src/kernel_tests/task_priority_reset.rs

@@ -0,0 +1,65 @@
+//! Checks that the task priority is reset whenever a task is activated.
+use constance::{
+    kernel::{cfg::CfgBuilder, Hunk, Task},
+    prelude::*,
+};
+
+use super::Driver;
+use crate::utils::SeqTracker;
+
+pub struct App<System> {
+    task2: Task<System>,
+    seq: Hunk<System, SeqTracker>,
+}
+
+impl<System: Kernel> App<System> {
+    pub const fn new<D: Driver<Self>>(b: &mut CfgBuilder<System>) -> Self {
+        Task::build()
+            .start(task1_body::<System, D>)
+            .priority(1)
+            .active(true)
+            .finish(b);
+        let task2 = Task::build()
+            .start(task2_body::<System, D>)
+            .priority(2)
+            .active(true)
+            .finish(b);
+
+        let seq = Hunk::<_, SeqTracker>::build().finish(b);
+
+        App { task2, seq }
+    }
+}
+
+fn task1_body<System: Kernel, D: Driver<App<System>>>(_: usize) {
+    // `task1` executes first because it has a higher priority.
+    D::app().seq.expect_and_replace(0, 1);
+
+    // Raise `task2`'s priority to higher than `task1`. `task2` will start
+    // executing.
+    D::app().task2.set_priority(0).unwrap();
+
+    // Back from `task2`...
+    D::app().seq.expect_and_replace(2, 3);
+
+    // Activate `task2` again. Its priority is back to the initial value
+    // (lower than `task1`). This time we don't raise its priority, so the
+    // system won't perform a context switch until `task1` exits.
+    D::app().task2.activate().unwrap();
+
+    D::app().seq.expect_and_replace(3, 4);
+
+    // Exit from `task1`, relinquishing the control to `task2`.
+}
+
+fn task2_body<System: Kernel, D: Driver<App<System>>>(_: usize) {
+    match D::app().seq.get() {
+        1 => {
+            D::app().seq.expect_and_replace(1, 2);
+        }
+        _ => {
+            D::app().seq.expect_and_replace(4, 5);
+            D::success();
+        }
+    }
+}

src/constance_test_suite/src/lib.rs

@@ -164,6 +164,7 @@ pub mod kernel_tests {
         (mod task_park_priority_boost {}, "task_park_priority_boost"),
         (mod task_park_reset {}, "task_park_reset"),
         (mod task_priority_boost_reset {}, "task_priority_boost_reset"),
+        (mod task_priority_reset {}, "task_priority_reset"),
         (mod task_queue_fifo {}, "task_queue_fifo"),
         (mod task_set_priority {}, "task_set_priority"),
         (mod task_take_interrupt_at_return {}, "task_take_interrupt_at_return"),