Added unit tests, Serial interface to talk to qemu device and log output from qemu device to console

Cargo.lock

@@ -31,6 +31,16 @@ dependencies = [
  "xmas-elf 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "cast"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "cc"
+version = "1.0.36"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "fixedvec"
 version = "0.2.3"
@@ -82,7 +92,9 @@ dependencies = [
  "bootloader 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "spin 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "uart_16550 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "volatile 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "x86_64 0.5.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -128,6 +140,16 @@ name = "rand_core"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "raw-cpuid"
+version = "6.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "bitflags 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cc 1.0.36 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "rdrand"
 version = "0.4.0"
@@ -144,6 +166,27 @@ dependencies = [
  "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "rustc_version"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "semver 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "semver"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "semver-parser 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "semver-parser"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "skeptic"
 version = "0.5.0"
@@ -172,6 +215,15 @@ dependencies = [
  "remove_dir_all 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "uart_16550"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "bitflags 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "x86_64 0.5.5 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "unicode-width"
 version = "0.1.5"
@@ -224,6 +276,19 @@ dependencies = [
  "ux 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "x86_64"
+version = "0.5.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "array-init 0.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "bit_field 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "bitflags 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cast 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "raw-cpuid 6.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ux 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "xmas-elf"
 version = "0.6.2"
@@ -242,6 +307,8 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum bit_field 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ed8765909f9009617974ab6b7d332625b320b33c326b1e9321382ef1999b5d56"
 "checksum bitflags 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)" = "bd1fa8ad26490b0a5cfec99089952250301b6716cdeaa7c9ab229598fb82ab66"
 "checksum bootloader 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)" = "8654b1ebbd38d2a8687a451ad53466d01b5edc9d75ec63d676525a6103d77151"
+"checksum cast 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "926013f2860c46252efceabb19f4a6b308197505082c609025aa6706c011d427"
+"checksum cc 1.0.36 (registry+https://github.com/rust-lang/crates.io-index)" = "a0c56216487bb80eec9c4516337b2588a4f2a2290d72a1416d930e4dcdb0c90d"
 "checksum fixedvec 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "7c6c16d316ccdac21a4dd648e314e76facbbaf316e83ca137d0857a9c07419d0"
 "checksum font8x8 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)" = "b81d84c3c978af7d05d31a2198af4b9ba956d819d15d8f6d58fc150e33f8dc1f"
 "checksum fuchsia-cprng 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "a06f77d526c1a601b7c4cdd98f54b5eaabffc14d5f2f0296febdc7f357c6d3ba"
@@ -255,12 +322,17 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum rand 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)" = "552840b97013b1a26992c11eac34bdd778e464601a4c2054b5f0bff7c6761293"
 "checksum rand_core 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7a6fdeb83b075e8266dcc8762c22776f6877a63111121f5f8c7411e5be7eed4b"
 "checksum rand_core 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d0e7a549d590831370895ab7ba4ea0c1b6b011d106b5ff2da6eee112615e6dc0"
+"checksum raw-cpuid 6.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "30a9d219c32c9132f7be513c18be77c9881c7107d2ab5569d205a6a0f0e6dc7d"
 "checksum rdrand 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "678054eb77286b51581ba43620cc911abf02758c91f93f479767aed0f90458b2"
 "checksum remove_dir_all 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "3488ba1b9a2084d38645c4c08276a1752dcbf2c7130d74f1569681ad5d2799c5"
+"checksum rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "138e3e0acb6c9fb258b19b67cb8abd63c00679d2851805ea151465464fe9030a"
+"checksum semver 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "1d7eb9ef2c18661902cc47e535f9bc51b78acd254da71d375c2f6720d9a40403"
+"checksum semver-parser 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3"
 "checksum skeptic 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "061203a849117b0f7090baf8157aa91dac30545208fbb85166ac58b4ca33d89c"
 "checksum spin 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)" = "ceac490aa12c567115b40b7b7fceca03a6c9d53d5defea066123debc83c5dc1f"
 "checksum spin 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "44363f6f51401c34e7be73db0db371c04705d35efbe9f7d6082e03a921a32c55"
 "checksum tempdir 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)" = "15f2b5fb00ccdf689e0149d1b1b3c03fead81c2b37735d812fa8bddbbf41b6d8"
+"checksum uart_16550 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "5b9392f60931fe3bf8f24e0a15ee4f51528770f1d64c48768ab66571334d95b0"
 "checksum unicode-width 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "882386231c45df4700b275c7ff55b6f3698780a650026380e72dabe76fa46526"
 "checksum usize_conversions 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "f70329e2cbe45d6c97a5112daad40c34cd9a4e18edb5a2a18fefeb584d8d25e5"
 "checksum ux 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "88dfeb711b61ce620c0cb6fd9f8e3e678622f0c971da2a63c4b3e25e88ed012f"
@@ -269,5 +341,6 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum winapi-i686-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
 "checksum winapi-x86_64-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
 "checksum x86_64 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)" = "f9258d7e2dd25008d69e8c9e9ee37865887a5e1e3d06a62f1cb3f6c209e6f177"
+"checksum x86_64 0.5.5 (registry+https://github.com/rust-lang/crates.io-index)" = "bb8f09c32a991cc758ebcb9b7984f530095d32578a4e7b85db6ee1f0bbe4c9c6"
 "checksum xmas-elf 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)" = "22678df5df766e8d1e5d609da69f0c3132d794edf6ab5e75e7abcd2270d4cf58"
 "checksum zero 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "5f1bc8a6b2005884962297587045002d8cfb8dcec9db332f4ca216ddc5de82c5"

Cargo.toml

@@ -8,6 +8,8 @@ edition = "2018"
 volatile = "0.2.3"
 spin = "0.4.6"
 bootloader = "0.6.0"
+x86_64 = "0.5.2"
+uart_16550 = "0.2.0"
 
 [dependencies.lazy_static]
 version = "1.0"
@@ -15,9 +17,17 @@ features = ["spin_no_std"]
 
 [package.metadata.bootimage]
 default-target = "neptune-x86_64.json"
-
+# iobase specifies the port address on which device should be available
-[build]
+# iosize specifies the port size
-target = "neptune-x86_64.json"
+# https://wiki.osdev.org/I/O_Ports#The_list
+#
+# Redirect serial output to console/terminal stdout
+#
+# Since, We are getting all test output in console, No need to create window when running tests
+test-args = ["-device", "isa-debug-exit,iobase=0xf4,iosize=0x04", "-serial", "mon:stdio", "-display", "none"]
+# test framework assumes every response code other than 0 to be an error
+# Change that default to 33 (0x10 << 1) | 1
+test-success-exit-code = 33
 
 [profile.dev]
 panic = "abort"

src/main.rs

@@ -1,28 +1,87 @@
-#![no_std] // don't include rust std lib
+// don't include rust std lib
-#![no_main] // disable all rust entry point
+#![no_std]
+// disable all rust entry point
+#![no_main]
+// Utilise custom test frameworks feature in rust, Since the default one doesn't works in no_std environments
+#![feature(custom_test_frameworks)]
+// Specify the runner, aka, The function that will execute all the tests
+#![test_runner(crate::test_runner)]
+// custom test frameworks creates an entry point called `main`. Since we are using no_main and have
+// set a custom entry point, The entry point created by custom test framework gets ignored.
+// This changes the name of the entry point to test_main which can then be called in _start
+#![reexport_test_harness_main = "test_main"]
 
 #[macro_use]
 extern crate lazy_static;
 
+mod serial;
 mod vga_buffer;
 
 use core::panic::PanicInfo;
-use vga_buffer::{Buffer, Color, ColorCode, Writer};
 
 /// This function is called on panic.
+#[cfg(not(test))]
 #[panic_handler]
 pub fn panic(info: &PanicInfo) -> ! {
     println!("{}", info);
     loop {}
 }
 
+#[cfg(test)]
+#[panic_handler]
+pub fn panic(info: &PanicInfo) -> ! {
+    serial_println!("[failed]\n");
+    serial_println!("Error: {}\n", info);
+    exit_qemu(QemuExitCode::Failed);
+    loop {}
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[repr(u32)]
+// u32 because iosize is set to 4 bytes
+pub enum QemuExitCode {
+    Success = 0x10,
+    Failed = 0x11,
+}
+
 #[no_mangle] // don't change the name of function in symbol table
 pub extern "C" fn _start() -> ! {
     use core::fmt::Write;
     vga_buffer::WRITER.lock().write_str("Hello again").unwrap();
     println!(", some numbers: {} {}", 42, 1.337);
 
-    panic!("panic message goes right here");
+    #[cfg(test)]
+    test_main();
 
     loop {}
 }
+
+pub fn exit_qemu(exit_code: QemuExitCode) {
+    use x86_64::instructions::port::Port;
+
+    unsafe {
+        // iobase address
+        let mut port = Port::new(0xf4);
+        port.write(exit_code as u32);
+    }
+}
+
+#[cfg(test)]
+fn test_runner(tests: &[&dyn Fn()]) {
+    println!("Running {} tests", tests.len());
+    serial_println!("Running {} tests", tests.len());
+
+    for test in tests {
+        test();
+    }
+    exit_qemu(QemuExitCode::Success);
+}
+
+#[test_case]
+fn trivial_assertion() {
+    print!("trivial assertion... ");
+    serial_print!("trivial assertion... ");
+    assert_eq!(1, 1);
+    println!("[ok]");
+    serial_println!("[ok]");
+}

src/serial.rs

@@ -0,0 +1,38 @@
+use lazy_static::lazy_static;
+use spin::Mutex;
+use uart_16550::SerialPort;
+
+lazy_static! {
+    pub static ref SERIAL: Mutex<SerialPort> = {
+        // 0x3F8 is a standard port addr for UART.
+        // It requires multiple ports but SerialPort implementation calculates rest of the ports
+        // automatically
+        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;
+    SERIAL
+        .lock()
+        .write_fmt(args)
+        .expect("Printing to serial failed!");
+}
+
+// Print to Serial Interface
+#[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)*));
+}

src/vga_buffer.rs

@@ -2,6 +2,9 @@ use core::fmt;
 use spin::Mutex;
 use volatile::Volatile;
 
+#[cfg(test)]
+use crate::{serial_print, serial_println};
+
 #[allow(dead_code)]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 #[repr(u8)]
@@ -151,3 +154,34 @@ pub fn _print(args: fmt::Arguments) {
     use core::fmt::Write;
     WRITER.lock().write_fmt(args).unwrap();
 }
+
+#[test_case]
+fn test_println_simple() {
+    serial_print!("test_println.. ");
+    println!("test_println_simple output");
+    serial_println!("[ok]");
+}
+
+#[test_case]
+fn test_println_many() {
+    serial_print!("test_println_many.. ");
+    for _i in 0..200 {
+        print!("test_println_many output goes here");
+    }
+    serial_println!("[ok]");
+}
+
+#[test_case]
+fn test_println_output() {
+    serial_print!("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);
+    }
+
+    serial_println!("[ok]");
+}