From cc2eabd500e6769136ee3601acb036a02c722570 Mon Sep 17 00:00:00 2001
From: lif <>
Date: Tue, 29 Apr 2025 02:12:56 -0700
Subject: [PATCH] unit test support

---
 src/main.rs         | 20 +++++++--
 src/test_harness.rs | 99 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 116 insertions(+), 3 deletions(-)
 create mode 100644 src/test_harness.rs

diff --git a/src/main.rs b/src/main.rs
index 7837450..9cdeb5e 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,12 +1,17 @@
-// from https://github.com/rust-console/gba/blob/main/examples/hello.rs
 #![no_std]
 #![no_main]
+#![cfg_attr(test, feature(custom_test_frameworks))]
+#![cfg_attr(test, test_runner(test_harness::test_runner))]
+#![cfg_attr(test, reexport_test_harness_main = "test_main")]
+
+#[cfg(test)]
+mod test_harness;
 
 use core::panic::PanicInfo;
 use gba::prelude::*;
 
 #[allow(unused_must_use)]
-#[unsafe(no_mangle)]
+#[cfg_attr(not(test), unsafe(no_mangle))]
 #[instruction_set(arm::t32)]
 extern "C" fn main() -> ! {
     BG_PALETTE.index(0).write(Color(0x7F2B)); // blue
@@ -33,7 +38,8 @@ extern "C" fn main() -> ! {
     unreachable!();
 }
 
-#[panic_handler]
+#[cfg_attr(not(test), panic_handler)]
+#[cfg_attr(test, allow(unused))]
 fn panic_handler(panic_info: &PanicInfo) -> ! {
     #[cfg(debug_assertions)]
     if let Ok(mut log) = MgbaBufferedLogger::try_new(MgbaMessageLevel::Fatal) {
@@ -48,3 +54,11 @@ fn panic_handler(panic_info: &PanicInfo) -> ! {
         VBlankIntrWait();
     }
 }
+
+#[cfg(test)]
+mod tests {
+    #[test_case]
+    fn it_works() {
+        assert_eq!(1 + 1, 2);
+    }
+}
diff --git a/src/test_harness.rs b/src/test_harness.rs
new file mode 100644
index 0000000..7e22928
--- /dev/null
+++ b/src/test_harness.rs
@@ -0,0 +1,99 @@
+use core::fmt::Write;
+use gba::{bios, mem, mgba, prelude::*};
+
+#[panic_handler]
+fn panic(info: &core::panic::PanicInfo) -> ! {
+    DISPSTAT.write(DisplayStatus::new().with_irq_vblank(true));
+    BG_PALETTE.index(0).write(Color::from_rgb(25, 10, 5));
+    IE.write(IrqBits::VBLANK);
+    IME.write(true);
+    VBlankIntrWait();
+    VBlankIntrWait();
+    VBlankIntrWait();
+
+    // the Fatal one kills emulation after one line / 256 bytes
+    // so emit all the information as Error first
+    if let Ok(mut log) = mgba::MgbaBufferedLogger::try_new(mgba::MgbaMessageLevel::Error) {
+        writeln!(log, "[failed]").ok();
+        write!(log, "{}", info).ok();
+    }
+
+    if let Ok(mut log) = mgba::MgbaBufferedLogger::try_new(mgba::MgbaMessageLevel::Fatal) {
+        if let Some(loc) = info.location() {
+            write!(log, "panic at {loc}! see mgba error log for details.").ok();
+        } else {
+            write!(log, "panic! see mgba error log for details.").ok();
+        }
+    }
+
+    IE.write(IrqBits::new());
+    bios::IntrWait(true, IrqBits::new());
+    loop {}
+}
+
+pub(crate) trait UnitTest {
+    fn run(&self);
+}
+
+impl<T: Fn()> UnitTest for T {
+    fn run(&self) {
+        if let Ok(mut log) = mgba::MgbaBufferedLogger::try_new(mgba::MgbaMessageLevel::Info) {
+            write!(log, "{}...", core::any::type_name::<T>()).ok();
+        }
+
+        self();
+
+        if let Ok(mut log) = mgba::MgbaBufferedLogger::try_new(mgba::MgbaMessageLevel::Info) {
+            writeln!(log, "[ok]").ok();
+        }
+    }
+}
+
+pub(crate) fn test_runner(tests: &[&dyn UnitTest]) {
+    if let Ok(mut log) = mgba::MgbaBufferedLogger::try_new(mgba::MgbaMessageLevel::Info) {
+        write!(log, "Running {} tests", tests.len()).ok();
+    }
+
+    for test in tests {
+        test.run();
+    }
+    if let Ok(mut log) = mgba::MgbaBufferedLogger::try_new(mgba::MgbaMessageLevel::Info) {
+        write!(log, "Tests finished successfully").ok();
+    }
+}
+
+#[unsafe(no_mangle)]
+extern "C" fn main() {
+    DISPCNT.write(DisplayControl::new().with_video_mode(VideoMode::_0));
+    BG_PALETTE.index(0).write(Color::new());
+
+    crate::test_main();
+
+    BG_PALETTE.index(0).write(Color::from_rgb(5, 15, 25));
+    BG_PALETTE.index(1).write(Color::new());
+    BG0CNT.write(
+        BackgroundControl::new()
+            .with_charblock(0)
+            .with_screenblock(31),
+    );
+    DISPCNT.write(
+        DisplayControl::new()
+            .with_video_mode(VideoMode::_0)
+            .with_show_bg0(true),
+    );
+
+    // some niceties for people without mgba-test-runner
+    let tsb = TEXT_SCREENBLOCKS.get_frame(31).unwrap();
+    unsafe {
+        mem::set_u32x80_unchecked(tsb.into_block::<1024>().as_mut_ptr().cast(), 0, 12);
+    }
+    Cga8x8Thick.bitunpack_4bpp(CHARBLOCK0_4BPP.as_region(), 0);
+
+    let row = tsb.get_row(9).unwrap().iter().skip(6);
+    for (addr, ch) in row.zip(b"all tests passed!") {
+        addr.write(TextEntry::new().with_tile(*ch as u16));
+    }
+
+    DISPSTAT.write(DisplayStatus::new());
+    bios::IntrWait(true, IrqBits::new());
+}