From bbe0551ac5e8786c28d4c7c0929e62fdac9ee714 Mon Sep 17 00:00:00 2001
From: janis <janis@nirgendwo.xyz>
Date: Sun, 19 Jul 2026 13:15:10 +0200
Subject: [PATCH] testing

---
 .gitignore             |  1 +
 kernel/Cargo.toml      |  6 +++++-
 kernel/build.rs        |  5 +++--
 kernel/run.sh          | 47 +++++++++++++++++++++++++++++++++++++-----
 kernel/src/lib.rs      |  8 +++++++
 kernel/src/testing.rs  | 37 +++++++++++++++++++++++++++++++++
 kernel/src/tests.rs    | 26 +++++++++++++++++++++++
 kernel/tests/simple.rs | 13 ++++++++++++
 8 files changed, 135 insertions(+), 8 deletions(-)
 create mode 100644 kernel/src/testing.rs
 create mode 100644 kernel/src/tests.rs
 create mode 100644 kernel/tests/simple.rs

diff --git a/.gitignore b/.gitignore
index 29963da..6884187 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 /.direnv/
+/kernel/qemu.log
diff --git a/kernel/Cargo.toml b/kernel/Cargo.toml
index a6c1c0b..ad92720 100644
--- a/kernel/Cargo.toml
+++ b/kernel/Cargo.toml
@@ -10,8 +10,12 @@ test = false
 bench = false
 
 [lib]
-test = false
+test = true
 bench = false
 
+[[test]]
+name = "simple"
+harness = false
+
 [dependencies]
 bitflags = "2.13.1"
diff --git a/kernel/build.rs b/kernel/build.rs
index 373fd84..a4f5cd9 100644
--- a/kernel/build.rs
+++ b/kernel/build.rs
@@ -1,6 +1,7 @@
 fn main() {
     println!("cargo::rerun-if-changed=build.rs");
-
-    println!("cargo::rustc-link-arg-bin=kernel=-Tkernel.lds");
     println!("cargo::rerun-if-changed=kernel.lds");
+
+    println!("cargo::rustc-link-arg=-Tkernel.lds");
+    // println!("cargo::rustc-link-arg-tests=-Tkernel.lds");
 }
diff --git a/kernel/run.sh b/kernel/run.sh
index 71a549d..dab2f71 100755
--- a/kernel/run.sh
+++ b/kernel/run.sh
@@ -8,16 +8,41 @@ canonicalised="$(realpath -- "$bin")"
 parent="$(dirname -- "$canonicalised")"
 bin_name="$(basename -- "$canonicalised")"
 
-image="$parent/$bin_name.img"
+parent_base="$(basename -- "$parent")"
 
+case "$parent_base" in
+    rustdoctest*)
+    is_doctest=1
+    ;;
+    *)
+    is_doctest=0
+    ;;
+esac
+
+case "$parent" in
+    */deps|*/deps/)
+    is_test=1
+    ;;
+    *)
+    is_test=$is_doctest
+    ;;
+esac
+
+echo "Running $bin_name (is_test=$is_test, is_doctest=$is_doctest)"
+
+if [[ $is_test -eq 1 ]]; then
+    QEMU_TEST_ARGS=("-display" "none" "-device" "isa-debug-exit,iobase=0xf4,iosize=0x04")
+else
+    QEMU_TEST_ARGS=()
+fi
+
+image="$parent/$bin_name.img"
 
 if [[ "$canonicalised" -nt "$image" ]]; then
     echo "Creating image $image"
 
     cat > /tmp/limine.conf <<EOF
 timeout: 0
-serial: yes
-serial_baudrate: 9600
 
 /Kernel
     protocol: limine
@@ -39,10 +64,22 @@ EOF
     mcopy -i "$image" "$limine_uefi_path" ::/EFI/BOOT/BOOTX64.EFI
 fi
 
+# cp -n "$OVMF_PATH/FV/OVMF_VARS.fd" "$parent/$bin_name.OVMF_VARS.fd"
+
+set +e
+
 qemu-system-x86_64 \
     -drive file="$image",format=raw \
     -machine q35,accel=kvm -enable-kvm \
     -drive if=pflash,format=raw,readonly=on,file="$OVMF_PATH/FV/OVMF_CODE.fd" \
-    -serial stdio \
-    -vga std
+    -chardev stdio,id=serial0,logfile=qemu.log,signal=off \
+    -serial chardev:serial0 \
+    -vga std \
+    ${QEMU_TEST_ARGS[@]}
+
+qemu_ret=$?
+
+if [[ $is_test -eq 1 ]]; then
+    exit $([ $qemu_ret -eq 33 ])
+fi
 
diff --git a/kernel/src/lib.rs b/kernel/src/lib.rs
index b57b12d..6145d17 100644
--- a/kernel/src/lib.rs
+++ b/kernel/src/lib.rs
@@ -1,11 +1,19 @@
 #![no_std]
 #![feature(const_trait_impl, const_default)]
+#![cfg_attr(test, feature(custom_test_frameworks))]
+#![cfg_attr(test, test_runner(crate::tests::test_runner))]
+#![cfg_attr(test, no_main)]
+#![cfg_attr(test, reexport_test_harness_main = "test_main")]
 
 pub mod limine;
 pub mod serial;
 pub mod sync;
 pub mod x86_64;
 
+pub mod testing;
+#[cfg(test)]
+mod tests;
+
 /// # Safety
 pub unsafe fn volatile_copy<T: Sized>(src: *const T, dst: *mut T, count: usize) {
     unsafe {
diff --git a/kernel/src/testing.rs b/kernel/src/testing.rs
new file mode 100644
index 0000000..ec0ef7e
--- /dev/null
+++ b/kernel/src/testing.rs
@@ -0,0 +1,37 @@
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[repr(u16)]
+pub enum QemuExitCode {
+    Success = 0x10,
+    Failed = 0x11,
+}
+
+pub fn exit_qemu(exit_code: QemuExitCode) -> ! {
+    use crate::x86_64::PortU16;
+
+    unsafe {
+        let port = PortU16(0xf4);
+        port.write(exit_code as u16);
+    }
+
+    crate::x86_64::halt_loop()
+}
+
+pub fn test_panic_handler(info: &core::panic::PanicInfo) -> ! {
+    crate::serial_println!("[PANIC] {}", info);
+    exit_qemu(QemuExitCode::Failed)
+}
+
+pub trait Testable {
+    fn run(&self);
+}
+
+impl<T> Testable for T
+where
+    T: Fn(),
+{
+    fn run(&self) {
+        crate::serial_print!("{}...\t", core::any::type_name::<T>());
+        self();
+        crate::serial_println!("[ok]");
+    }
+}
diff --git a/kernel/src/tests.rs b/kernel/src/tests.rs
new file mode 100644
index 0000000..c19763a
--- /dev/null
+++ b/kernel/src/tests.rs
@@ -0,0 +1,26 @@
+use crate::testing::{QemuExitCode, Testable, exit_qemu};
+
+pub fn test_runner(tests: &[&dyn Testable]) {
+    crate::serial_println!("Running {} tests", tests.len());
+    for test in tests {
+        test.run();
+    }
+
+    crate::serial_println!("[ok] All tests passed");
+}
+
+#[panic_handler]
+fn panic_thunk(info: &core::panic::PanicInfo) -> ! {
+    crate::testing::test_panic_handler(info)
+}
+
+#[unsafe(export_name = "_start")]
+fn main() -> ! {
+    crate::test_main();
+    exit_qemu(QemuExitCode::Success)
+}
+
+// #[test_case]
+// fn panics() {
+//     panic!("This test should panic");
+// }
diff --git a/kernel/tests/simple.rs b/kernel/tests/simple.rs
new file mode 100644
index 0000000..7f9cd03
--- /dev/null
+++ b/kernel/tests/simple.rs
@@ -0,0 +1,13 @@
+#![no_main]
+#![no_std]
+
+#[unsafe(export_name = "_start")]
+pub extern "C" fn main() -> ! {
+    kernel::serial_println!("Hello, world!");
+    kernel::testing::exit_qemu(kernel::testing::QemuExitCode::Success)
+}
+
+#[panic_handler]
+fn panic_thunk(info: &core::panic::PanicInfo) -> ! {
+    kernel::testing::test_panic_handler(info)
+}