diff --git a/Cargo.lock b/Cargo.lock
index bb298fa..a1de5cb 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2,6 +2,24 @@
 # It is not intended for manual editing.
 version = 4
 
+[[package]]
+name = "bit_field"
+version = "0.10.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dc827186963e592360843fb5ba4b973e145841266c1357f7180c43526f2e5b61"
+
+[[package]]
+name = "bitflags"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
+
+[[package]]
+name = "bitflags"
+version = "2.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b048fb63fd8b5923fc5aa7b340d8e156aec7ec02f0c78fa8a6ddc2613f6f71de"
+
 [[package]]
 name = "bootloader"
 version = "0.9.29"
@@ -15,7 +33,9 @@ dependencies = [
  "bootloader",
  "lazy_static",
  "spin 0.5.2",
- "volatile",
+ "uart_16550",
+ "volatile 0.2.7",
+ "x86_64",
 ]
 
 [[package]]
@@ -27,6 +47,12 @@ dependencies = [
  "spin 0.9.8",
 ]
 
+[[package]]
+name = "rustversion"
+version = "1.0.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0e819f2bc632f285be6d7cd36e25940d45b2391dd6d9b939e79de557f7014248"
+
 [[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 2.6.0",
+ "rustversion",
+ "volatile 0.4.6",
+]
diff --git a/Cargo.toml b/Cargo.toml
index 41f3157..a79ce8f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -16,7 +16,14 @@ build-std = ["core", "compiler_builtins"]
 bootloader = "0.9"
 volatile = "0.2.6"
 spin = "0.5.2"
+x86_64 = "0.14.2"
+uart_16550 = "0.2.0"
 
 [dependencies.lazy_static]
 version = "1.0"
 features = ["spin_no_std"]
+
+[package.metadata.bootimage]
+test-args = ["-device", "isa-debug-exit,iobase=0xf4,iosize=0x04", "-serial", "stdio"]
+test-success-exit-code = 33
+
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..c2297b9
--- /dev/null
+++ b/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 {}
+}
+
+/// Entry point for `cargo test`
+#[cfg(test)]
+#[no_mangle]
+pub extern "C" fn _start() -> ! {
+    test_main();
+    loop {}
+}
+
+#[cfg(test)]
+#[panic_handler]
+fn panic(info: &PanicInfo) -> ! {
+    test_panic_handler(info)
+}
+
+#[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);
+        port.write(exit_code as u32);
+    }
+}
\ No newline at end of file
diff --git a/src/main.rs b/src/main.rs
index 92fc77b..6f32daf 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,39 +1,32 @@
-#![allow()]
 #![no_std]
 #![no_main]
 #![feature(custom_test_frameworks)]
-#![test_runner(crate::test_runner)]
+#![test_runner(donald::test_runner)]
 #![reexport_test_harness_main = "test_main"]
 
-#[cfg(test)]
-pub fn test_runner(tests: &[&dyn Fn()]) {
-    println!("Running {} tests", tests.len());
-    for test in tests {
-        test();
-    }
-}
-mod vga_buffer;
-
 use core::panic::PanicInfo;
-#[panic_handler]
-fn panic(info: &PanicInfo) -> ! {
-    println!("{}", info);
-    loop {}
-}
-
+use donald::println;
 
 #[no_mangle]
 pub extern "C" fn _start() -> ! {
-    println!("Hello World!");
+    println!("Hello World{}", "!");
+
     #[cfg(test)]
     test_main();
 
     loop {}
 }
 
-#[test_case]
-fn trivial_assertion() {
-    print!("trivial assertion... ");
-    assert_eq!(1, 1);
-    println!("[ok]");
+/// This function is called on panic.
+#[cfg(not(test))]
+#[panic_handler]
+fn panic(info: &PanicInfo) -> ! {
+    println!("{}", info);
+    loop {}
 }
+
+#[cfg(test)]
+#[panic_handler]
+fn panic(info: &PanicInfo) -> ! {
+    donald::test_panic_handler(info)
+}
\ No newline at end of file
diff --git a/src/serial.rs b/src/serial.rs
new file mode 100644
index 0000000..5c575ac
--- /dev/null
+++ b/src/serial.rs
@@ -0,0 +1,35 @@
+// Handles a serial port (uart_16550)
+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) };
+        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)*));
+}
diff --git a/src/vga_buffer.rs b/src/vga_buffer.rs
index 8a44798..256129a 100644
--- a/src/vga_buffer.rs
+++ b/src/vga_buffer.rs
@@ -141,4 +141,26 @@ macro_rules! println {
 pub fn _print(args: fmt::Arguments) {
     use core::fmt::Write;
     WRITER.lock().write_fmt(args).unwrap();
+}
+
+#[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);
+    }
 }
\ No newline at end of file
diff --git a/tests/basic_boot.rs b/tests/basic_boot.rs
new file mode 100644
index 0000000..b814c56
--- /dev/null
+++ b/tests/basic_boot.rs
@@ -0,0 +1,32 @@
+// Basic boot test
+
+#![no_std]
+#![no_main]
+#![feature(custom_test_frameworks)]
+#![test_runner(donald::test_runner)]
+#![reexport_test_harness_main = "test_main"]
+
+use core::panic::PanicInfo;
+
+#[no_mangle] // don't mangle the name of this function
+pub extern "C" fn _start() -> ! {
+    test_main();
+
+    loop {}
+}
+
+fn test_runner(tests: &[&dyn Fn()]) {
+    unimplemented!();
+}
+
+#[panic_handler]
+fn panic(info: &PanicInfo) -> ! {
+    donald::test_panic_handler(info)
+}
+
+use donald::println;
+
+#[test_case]
+fn test_println() {
+    println!("test_println output");
+}
\ No newline at end of file