Tests and test output over serial working

.cargo/config

@@ -5,3 +5,6 @@ build-std-features = ["compiler-builtins-mem"]
 [build]
 target = "x86_64_target.json"
 
+# Facilitates running tests with qemu
+[target.'cfg(target_os = "none")']
+runner = "bootimage runner"

Cargo.lock

@@ -2,6 +2,18 @@
 # It is not intended for manual editing.
 version = 3
 
+[[package]]
+name = "bit_field"
+version = "0.10.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dcb6dd1c2376d2e096796e234a70e17e94cc2d5d54ff8ce42b28cef1d0d359a4"
+
+[[package]]
+name = "bitflags"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
+
 [[package]]
 name = "bootloader"
 version = "0.9.21"
@@ -33,6 +45,8 @@ dependencies = [
  "bootloader",
  "lazy_static",
  "spin 0.9.2",
+ "uart_16550",
+ "x86_64",
 ]
 
 [[package]]
@@ -55,3 +69,30 @@ checksum = "511254be0c5bcf062b019a6c89c01a664aa359ded62f78aa72c6fc137c0590e5"
 dependencies = [
  "lock_api",
 ]
+
+[[package]]
+name = "uart_16550"
+version = "0.2.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "af81448a9a53c7b0f66198381f80912fd18f2c8965f9da4319e6f92e740bca5b"
+dependencies = [
+ "bitflags",
+ "x86_64",
+]
+
+[[package]]
+name = "volatile"
+version = "0.4.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e4c2dbd44eb8b53973357e6e207e370f0c1059990df850aca1eca8947cf464f0"
+
+[[package]]
+name = "x86_64"
+version = "0.14.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "958ab3202b01bc43ba2eb832102c4a487ed93151667a2289062e5f2b00058be2"
+dependencies = [
+ "bit_field",
+ "bitflags",
+ "volatile",
+]

Cargo.toml

@@ -8,8 +8,14 @@ edition = "2021"
 #bootloader = "0.10.12"
 bootloader = "0.9.8"
 spin = "0.9.2"
+x86_64 = "0.14.8"
+uart_16550 = "0.2.16"
 
 [dependencies.lazy_static]
 version = "1.4.0"
 features = ["spin_no_std"]
 
+
+[package.metadata.bootimage]
+test-args = ["-device", "isa-debug-exit,iobase=0xf4,iosize=0x04", "-serial", "stdio"]
+test-success-exit-code = 33 # (0x10 << 1) | 1

src/main.rs

@@ -2,8 +2,14 @@
 #![no_std]
 #![no_main]
 
+#![feature(custom_test_frameworks)]
+#![test_runner(crate::test_runner)]
+#![reexport_test_harness_main = "test_main"]
+
 #[macro_use]
 mod vga_buffer;
+#[macro_use]
+mod serial;
 
 use core::panic::PanicInfo;
 
@@ -15,6 +21,42 @@ fn panic(info: &PanicInfo) -> ! {
 
 #[no_mangle]
 pub extern "C" fn _start() -> ! {
+    #[cfg(test)]
+    test_main();
+
     println!("Gamarjoba, munde!");
     loop {}
 }
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[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); // isa-debug-exit port, see Cargo.toml
+        port.write(exit_code as u32);
+    }
+}
+
+#[cfg(test)]
+fn test_runner(tests: &[&dyn Fn()]) {
+    serial_println!("Running {} test(s)", tests.len());
+    for test in tests {
+        test();
+    }
+
+    exit_qemu(QemuExitCode::Success);
+}
+
+#[test_case]
+fn basic_test() {
+    serial_print!("Trivial test... ");
+    assert_eq!(5, 5);
+    serial_println!("[ok]");
+}
+

src/serial.rs

@@ -0,0 +1,33 @@
+use uart_16550::SerialPort;
+use spin::Mutex;
+use lazy_static::lazy_static;
+
+
+lazy_static! {
+    pub static ref SERIAL1: Mutex<SerialPort> = {
+        let mut serial_port = unsafe { SerialPort::new(0x3f8) }; // 0x3f8 is standard address of 1st serial port
+        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("Serial print failed");
+}
+
+#[macro_export]
+macro_rules! serial_print {
+    ($($arg:tt)*) => {
+        $crate::serial::_print(format_args!($($arg)*));
+    };
+}
+
+#[macro_export]
+macro_rules! serial_println {
+    () => ($crate::serial_print!("\n"));
+    ($fmt:expr) => ($crate::serial_print!(concat!($fmt, "\n")));
+    ($fmt:expr, $($arg:tt)*) => ($crate::serial_print!(
+            concat!($fmt, "\n"), $($arg)*));
+}