add what's required for cargo test

.cargo/config.toml

@@ -1,10 +1,10 @@
 [unstable]
-build-std = ["core", "compiler_builtins", "alloc"]
+build-std = ["core"]
 build-std-features = ["compiler-builtins-mem"]
 
 [build]
 target = "thumbv4t-none-eabi"
 
 [target.thumbv4t-none-eabi]
-runner = "mgba-qt -l 31 -d -C logToStdout=1"
 rustflags = ["-Clink-arg=-Tgba.ld"]
+runner = "mgba-test-runner"

Cargo.toml

@@ -6,8 +6,6 @@ edition = "2018"
 
 [profile.dev]
 opt-level = 2
-panic = "abort"
-lto = true
 
 [profile.release]
 panic = "abort"

src/lib.rs

@@ -1,6 +1,10 @@
 #![no_std]
+#![no_main]
 #![feature(asm)]
 #![deny(clippy::all)]
+#![feature(custom_test_frameworks)]
+#![test_runner(crate::test_runner)]
+#![reexport_test_harness_main = "test_main"]
 
 use core::fmt::Write;
 pub mod display;
@@ -13,6 +17,7 @@ mod single;
 
 pub mod syscall;
 
+#[cfg(not(test))]
 #[panic_handler]
 #[allow(unused_must_use)]
 fn panic_implementation(info: &core::panic::PanicInfo) -> ! {
@@ -24,8 +29,12 @@ fn panic_implementation(info: &core::panic::PanicInfo) -> ! {
     loop {}
 }
 
+#[cfg(not(test))]
 static mut GBASINGLE: single::Singleton<Gba> = single::Singleton::new(unsafe { Gba::single_new() });
 
+#[cfg(test)]
+static mut GBASINGLE: single::Singleton<Gba> = single::Singleton::empty();
+
 pub struct Gba {
     pub display: display::Display,
 }
@@ -47,3 +56,77 @@ impl Default for Gba {
         Self::new()
     }
 }
+
+pub trait Testable {
+    fn run(&self, gba: &mut Gba) -> ();
+}
+
+impl<T> Testable for T
+where
+    T: Fn(&mut Gba),
+{
+    fn run(&self, gba: &mut Gba) {
+        let mut mgba = mgba::Mgba::new().unwrap();
+        mgba.print(
+            format_args!("{}...", core::any::type_name::<T>()),
+            mgba::DebugLevel::Info,
+        );
+        self(gba);
+        mgba.print(format_args!("[ok]"), mgba::DebugLevel::Info);
+    }
+}
+
+#[panic_handler]
+#[cfg(test)]
+fn panic_implementation(info: &core::panic::PanicInfo) -> ! {
+    if let Some(mut mgba) = mgba::Mgba::new() {
+        mgba.print(format_args!("[failed]"), mgba::DebugLevel::Error);
+        mgba.print(format_args!("Error: {}", info), mgba::DebugLevel::Fatal);
+    }
+
+    loop {}
+}
+
+pub fn test_runner(tests: &[&dyn Testable]) {
+    let mut mgba = mgba::Mgba::new().unwrap();
+    mgba.print(
+        format_args!("Running {} tests", tests.len()),
+        mgba::DebugLevel::Info,
+    );
+
+    let mut gba = unsafe { Gba::single_new() };
+
+    for test in tests {
+        test.run(&mut gba);
+    }
+
+    mgba.print(
+        format_args!("Tests finished successfully"),
+        mgba::DebugLevel::Info,
+    );
+}
+
+#[no_mangle]
+#[cfg(test)]
+pub extern "C" fn main() -> ! {
+    test_main();
+    loop {}
+}
+
+#[test_case]
+fn trivial_test(_gba: &mut Gba) {
+    assert_eq!(1, 1);
+}
+
+#[test_case]
+fn wait_30_frames(gba: &mut Gba) {
+    let vblank = gba.display.vblank.get();
+    let mut counter = 0;
+    loop {
+        if counter > 30 {
+            break;
+        }
+        vblank.wait_for_VBlank();
+        counter += 1
+    }
+}

src/single.rs

@@ -6,10 +6,17 @@ impl<T> Singleton<T> {
     pub const fn new(s: T) -> Self {
         Singleton { single: Some(s) }
     }
+    pub const fn empty() -> Self {
+        Singleton { single: None }
+    }
     pub fn take(&mut self) -> T {
         let g = core::mem::replace(&mut self.single, None);
         g.unwrap()
     }
+
+    pub fn ret(&mut self, ret: T) {
+        self.single = Some(ret);
+    }
 }
 
 pub struct Single {