Support integration testing

Cargo.lock

@@ -2,6 +2,24 @@
 # It is not intended for manual editing.
 version = 4
 
+[[package]]
+name = "bit_field"
+version = "0.10.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e4b40c7323adcfc0a41c4b88143ed58346ff65a288fc144329c5c45e05d70c6"
+
+[[package]]
+name = "bitflags"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
+
+[[package]]
+name = "bitflags"
+version = "2.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "843867be96c8daad0d758b57df9392b6d8d271134fce549de6ce169ff98a92af"
+
 [[package]]
 name = "bootloader"
 version = "0.9.34"
@@ -24,9 +42,17 @@ dependencies = [
  "bootloader",
  "lazy_static",
  "spin 0.5.2",
- "volatile",
+ "uart_16550",
+ "volatile 0.2.7",
+ "x86_64",
 ]
 
+[[package]]
+name = "rustversion"
+version = "1.0.22"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b39cdef0fa800fc44525c84ccb54a029961a8215f9619753635a9c0d2538d46d"
+
 [[package]]
 name = "spin"
 version = "0.5.2"
@@ -39,8 +65,37 @@ version = "0.9.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6980e8d7511241f8acf4aebddbb1ff938df5eebe98691418c4468d0b72a96a67"
 
+[[package]]
+name = "uart_16550"
+version = "0.2.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "614ff2a87880d4bd4374722268598a970bbad05ced8bf630439417347254ab2e"
+dependencies = [
+ "bitflags 1.3.2",
+ "rustversion",
+ "x86_64",
+]
+
 [[package]]
 name = "volatile"
 version = "0.2.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f6b06ad3ed06fef1713569d547cdbdb439eafed76341820fb0e0344f29a41945"
+
+[[package]]
+name = "volatile"
+version = "0.4.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "442887c63f2c839b346c192d047a7c87e73d0689c9157b00b53dcc27dd5ea793"
+
+[[package]]
+name = "x86_64"
+version = "0.14.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c101112411baafbb4bf8d33e4c4a80ab5b02d74d2612331c61e8192fc9710491"
+dependencies = [
+ "bit_field",
+ "bitflags 2.11.0",
+ "rustversion",
+ "volatile 0.4.6",
+]

Cargo.toml

@@ -5,19 +5,32 @@ edition = "2024"
 authors = ["Ahmed Nagi"]
 
 [profile.dev]
-panic = "abort"
-
+# panic = "abort"
 
 [profile.release]
 panic = "abort"
 
 [[bin]]
 name = "rust-kernel"
-test = false 
+test = true 
 bench = false
 
+[package.metadata.bootimage]
+test-args = [
+    "-device", "isa-debug-exit,iobase=0xf4,iosize=0x04", "-serial", "stdio",
+    "-display", "none"
+]
+test-success-exit-code = 33
+test-timeout = 300          # (in seconds)
+
+[[test]]
+name = "should_panic"
+harness = false
+
 [dependencies]
 bootloader = "0.9"
 volatile = "0.2.6"
 lazy_static = { version = "1.5", features = ["spin_no_std"] }
 spin = "0.5.2"
+x86_64 = "0.14.2"
+uart_16550 = "0.2.0"

src/lib.rs

@@ -0,0 +1,71 @@
+#![no_std]
+#![cfg_attr(test, no_main)]
+#![feature(custom_test_frameworks)]
+#![test_runner(crate::test_runner)]
+#![reexport_test_harness_main = "test_main"]
+
+pub mod serial;
+pub mod vga_buffer;
+
+use core::panic::PanicInfo;
+
+pub trait Testable {
+    fn run(&self);
+}
+
+impl<T> Testable for T
+where
+    T: Fn(),
+{
+    fn run(&self) {
+        serial_print!("{}...\t", core::any::type_name::<T>());
+        self();
+        serial_println!("[ok]");
+    }
+}
+
+pub fn test_runner(tests: &[&dyn Testable]) {
+    serial_println!("Running {} tests", tests.len());
+
+    for test in tests {
+        test.run();
+    }
+    exit_qemu(QemuExitCode::Success);
+}
+
+pub fn test_panic_handler(info: &PanicInfo) -> ! {
+    serial_println!("[failed]\n");
+    serial_println!("Error: {}\n", info);
+    exit_qemu(QemuExitCode::Failed);
+
+    loop {}
+}
+
+#[repr(u32)]
+pub enum QemuExitCode {
+    Success = 0x10,
+    Failed = 0x11,
+}
+
+pub fn exit_qemu(exit_code: QemuExitCode) {
+    use x86_64::instructions::port::Port;
+
+    unsafe {
+        let mut port = Port::new(0xf4);
+        port.write(exit_code as u32);
+    }
+}
+
+// Entry point for `cargo test`
+#[cfg(test)]
+#[unsafe(no_mangle)]
+pub extern "C" fn _start() -> ! {
+    test_main();
+    loop {}
+}
+
+#[cfg(test)]
+#[panic_handler]
+fn panic(info: &PanicInfo) -> ! {
+    test_panic_handler(info)
+}

src/main.rs

@@ -1,19 +1,32 @@
 #![no_std]
 #![no_main]
-
-mod vga_buffer;
+#![feature(custom_test_frameworks)]
+#![test_runner(rust_kernel::test_runner)]
+#![reexport_test_harness_main = "test_main"]
 
 use core::panic::PanicInfo;
+use rust_kernel::println;
 
 #[unsafe(no_mangle)]
 pub extern "C" fn _start() -> ! {
     println!("Hello World{}", "!");
-    panic!("Some panic message");
+
+    #[cfg(test)]
+    test_main();
+
     loop {}
 }
 
+// called on panic.
+#[cfg(not(test))]
 #[panic_handler]
 fn panic(info: &PanicInfo) -> ! {
-    println!("{info}");
+    println!("{}", info);
     loop {}
 }
+
+#[cfg(test)]
+#[panic_handler]
+fn panic(info: &PanicInfo) -> ! {
+    rust_kernel::test_panic_handler(info)
+}

src/serial.rs

@@ -0,0 +1,37 @@
+use lazy_static::lazy_static;
+use spin::Mutex;
+use uart_16550::SerialPort;
+
+lazy_static! {
+    pub static ref SERIAL1: Mutex<SerialPort> = {
+        let mut serial_port = unsafe { SerialPort::new(0x3F8) };
+        serial_port.init();
+        Mutex::new(serial_port)
+    };
+}
+
+#[doc(hidden)]
+pub fn _print(args: ::core::fmt::Arguments) {
+    use core::fmt::Write;
+    SERIAL1
+        .lock()
+        .write_fmt(args)
+        .expect("Printing to serial failed");
+}
+
+/// Prints to the host through the serial interface.
+#[macro_export]
+macro_rules! serial_print {
+    ($($arg:tt)*) => {
+        $crate::serial::_print(format_args!($($arg)*));
+    };
+}
+
+/// Prints to the host through the serial interface, appending a newline.
+#[macro_export]
+macro_rules! serial_println {
+    () => ($crate::serial_print!("\n"));
+    ($fmt:expr) => ($crate::serial_print!(concat!($fmt, "\n")));
+    ($fmt:expr, $($arg:tt)*) => ($crate::serial_print!(
+        concat!($fmt, "\n"), $($arg)*));
+}

src/vga_buffer.rs

@@ -39,16 +39,16 @@ impl ColorCode {
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 #[repr(C)]
 struct ScreenChar {
-    ascii_character: u8,
-    color_code: ColorCode,
+    pub ascii_character: u8,
+    pub color_code: ColorCode,
 }
 
-const BUFFER_HEIGHT: usize = 25;
-const BUFFER_WIDTH: usize = 80;
+pub const BUFFER_HEIGHT: usize = 25;
+pub const BUFFER_WIDTH: usize = 80;
 
 #[repr(transparent)]
 struct Buffer {
-    chars: [[Volatile<ScreenChar>; BUFFER_WIDTH]; BUFFER_HEIGHT],
+    pub chars: [[Volatile<ScreenChar>; BUFFER_WIDTH]; BUFFER_HEIGHT],
 }
 
 pub struct Writer {
@@ -142,3 +142,31 @@ pub fn _print(args: fmt::Arguments) {
     use core::fmt::Write;
     WRITER.lock().write_fmt(args).unwrap();
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    
+    #[test_case]
+    fn test_println_simple() {
+        println!("test_println_simple output");
+    }
+    
+    #[test_case]
+    fn test_println_many() {
+        for _ in 0..200 {
+            println!("test_println_many output")
+        }
+    }
+    
+    #[test_case]
+    fn test_println_output() {
+        let s = "Some test string that fits on a single line";
+        println!("{s}");
+
+        for (i, c) in s.chars().enumerate() {
+            let screen_char = WRITER.lock().buffer.chars[BUFFER_HEIGHT - 2][i].read();
+            assert_eq!(char::from(screen_char.ascii_character), c)
+        }
+    }
+}

tests/basic_boot.rs

@@ -0,0 +1,25 @@
+#![no_std]
+#![no_main]
+#![feature(custom_test_frameworks)]
+#![test_runner(rust_kernel::test_runner)]
+#![reexport_test_harness_main = "test_main"]
+
+use core::panic::PanicInfo;
+
+use rust_kernel::println;
+
+#[unsafe(no_mangle)]
+pub extern "C" fn _start() -> ! {
+    test_main();
+    loop {}
+}
+
+#[panic_handler]
+fn panic(info: &PanicInfo) -> ! {
+    rust_kernel::test_panic_handler(info)
+}
+
+#[test_case]
+fn test_println() {
+    println!("test_println output");
+}

tests/should_panic.rs

@@ -0,0 +1,25 @@
+#![no_std]
+#![no_main]
+
+use core::panic::PanicInfo;
+use rust_kernel::{QemuExitCode, exit_qemu, serial_print, serial_println};
+
+#[unsafe(no_mangle)]
+pub extern "C" fn _start() -> ! {
+    should_fail();
+    serial_println!("[test did not panic]");
+    exit_qemu(QemuExitCode::Failed);
+    loop {}
+}
+
+fn should_fail() {
+    serial_print!("should_panic::should_fail...\t");
+    assert_eq!(0, 1);
+}
+
+#[panic_handler]
+fn panic(_info: &PanicInfo) -> ! {
+    serial_println!("[ok]");
+    exit_qemu(QemuExitCode::Success);
+    loop {}
+}