feat(testing): add basic section-based test declaration support (#65)

Implements a section-based approach for declaring tests within the kernel from across the dependency graph with a single test runner.

In addition, fixes a number of host tests to allow them to run under CI.

Example Output:
```
 [INFO] run tests
 [INFO] | test, test.name="basic_alloc", test.module="mycelium_kernel"
 [INFO] | |- mycelium_kernel: vec=[], vec.addr=0x8
 [INFO] | |- mycelium_kernel: vec=[5], vec.addr=0x3fc058
 [INFO] | |- mycelium_kernel: vec=[5, 10], vec.addr=0x3fc048
 [INFO] | test, test.name="wasm_hello_world", test.module="mycelium_kernel"
[TRACE] | | invoke_index, index=0, args=RuntimeArgs([I32(1), I32(0), I32(1), I32(20)])
 [INFO] | | | fd_write, fd=1, iovs=0, iovs_len=1, nwritten=20
 [INFO] | | | |- mycelium_kernel::wasm::wasi: fd_write, buf_slice=[104, 101, 108, 108, 111, 32, 119, 111, 114, 108, 100, 10], buf_str=Ok("hello world\n")
 [INFO] | test, test.name="it_works", test.module="mycelium_util::testing"
 [INFO] | |- mycelium_util::testing: I'm running in a test!
 [WARN] |- mycelium_kernel: 3 passed | 0 failed
```

.cargo/config

@@ -5,3 +5,4 @@ runner = "bootimage runner"
 dev-env = "install cargo-xbuild bootimage"
 run-x64 = "xrun --target=x86_64-mycelium.json"
 debug-x64 = "xrun --target=x86_64-mycelium.json -- -gdb tcp::1234 -S"
+test-x64 = "xtest --target=x86_64-mycelium.json"

.github/workflows/rust.yml

@@ -22,17 +22,55 @@ jobs:
       with:
         command: bootimage
         args: --target=x86_64-mycelium.json
-    - name: Test
+
+  test:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v1
+    - name: install rust toolchain
+      uses: actions-rs/toolchain@v1
+      with:
+        profile: minimal
+        toolchain: nightly
+        components: rust-src, llvm-tools-preview
+    - name: install dev env
+      uses: actions-rs/cargo@v1.0.1
+      with:
+        command: dev-env
+    - name: install qemu
+      run: sudo apt-get update && sudo apt-get install qemu
+    - name: run tests
+      uses: actions-rs/cargo@v1.0.1
+      with:
+        command: test-x64
+
+  host-test:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v1
+    - name: install rust toolchain
+      uses: actions-rs/toolchain@v1
+      with:
+        profile: minimal
+        toolchain: nightly
+    - name: run host tests
       uses: actions-rs/cargo@v1.0.1
       with:
         command: test
+        args: --all --all-features
 
   clippy:
     runs-on: ubuntu-latest
     needs: build
     steps:
     - uses: actions/checkout@v1
+    - uses: actions-rs/toolchain@v1
+      with:
+        profile: minimal
+        toolchain: nightly
+        components: clippy
     - name: rust-clippy-check
       uses: actions-rs/clippy-check@v1.0.5
       with:
         token: ${{ secrets.GITHUB_TOKEN }}
+        args: --all-features

Cargo.toml

@@ -14,10 +14,17 @@ edition = "2018"
 
 [lib]
 name = "mycelium_kernel"
+harness = false
+
+[[bin]]
+name = "mycelium_kernel"
+path = "src/main.rs"
+test = false
 
 [dependencies]
 hal-core = { path = "hal-core" }
 mycelium-alloc = { path = "alloc" }
+mycelium-util = { path = "util" }
 tracing = { version = "0.1", default_features = false }
 
 [target.'cfg(target_arch = "x86_64")'.dependencies]
@@ -35,6 +42,11 @@ wat = "1.0"
 
 [package.metadata.bootimage]
 default-target = "x86_64-mycelium.json"
+test-success-exit-code = 33 # (0x10 << 1) | 1
+test-args = [
+    "-device", "isa-debug-exit,iobase=0xf4,iosize=0x04",
+    "-serial", "stdio", "-display", "none"
+]
 
 [package.metadata.target.'cfg(target_arch = "x86_64")'.cargo-xbuild]
 memcpy = true

alloc/src/lib.rs

@@ -2,7 +2,7 @@
 //! Allocates into a "large" static array.
 #![no_std]
 
-use core::alloc::{Layout, GlobalAlloc};
+use core::alloc::{GlobalAlloc, Layout};
 use core::cell::UnsafeCell;
 use core::mem::MaybeUninit;
 use core::ptr;
@@ -14,7 +14,7 @@ macro_rules! try_null {
             Some(x) => x,
             None => return ptr::null_mut(),
         }
-    }
+    };
 }
 
 // 640k is enough for anyone
@@ -85,7 +85,7 @@ mod test {
         assert_eq!(p0.align_offset(mem::align_of::<u32>()), 0);
         assert_eq!(p1.align_offset(mem::align_of::<u32>()), 0);
 
-        assert_eq!((p1 as usize) - (p0 as usize), 4);
+        assert_eq!((p0 as usize) - (p1 as usize), 4);
     }
 
     #[test]
@@ -99,8 +99,8 @@ mod test {
         let p2 = unsafe { alloc(Layout::new::<u32>()) };
         assert!(!p2.is_null());
 
-        assert_eq!((p1 as usize) - (p0 as usize), 1);
-        assert!((p2 as usize) - (p1 as usize) > 0);
+        assert_eq!((p0 as usize) - (p1 as usize), 1);
+        assert!((p1 as usize) - (p2 as usize) > 0);
 
         assert_eq!(p2.align_offset(mem::align_of::<u32>()), 0);
     }

hal-core/src/addr.rs

@@ -40,7 +40,7 @@ pub trait Address:
     /// This is equivalent to
     /// ```rust
     /// # use hal_core::Address;
-    /// # fn doc<A: Address>(addr: A) -> A {
+    /// # fn doc<T: Address>(addr: T) -> T {
     /// addr.align_up(core::mem::align_of::<T>())
     /// # }
     /// ````
@@ -68,7 +68,7 @@ pub trait Address:
     /// This is equivalent to
     /// ```rust
     /// # use hal_core::Address;
-    /// # fn doc<A: Address>(addr: A) -> A {
+    /// # fn doc<T: Address>(addr: T) -> T {
     /// addr.align_down(core::mem::align_of::<T>())
     /// # }
     /// ````

src/arch/x86_64.rs

@@ -153,9 +153,38 @@ pub fn oops(cause: &dyn core::fmt::Display) -> ! {
     let _ = writeln!(vga, "\n  uwu we did a widdle fucky-wucky!\n{}", cause);
     let _ = vga.write_str("\n  it will never be safe to turn off your computer.");
 
+    #[cfg(test)]
+    qemu_exit(QemuExitCode::Failed);
+
+    #[cfg(not(test))]
     loop {
         unsafe {
             asm!("hlt" :::: "volatile");
         }
     }
 }
+
+#[cfg(test)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[repr(u32)]
+pub(crate) enum QemuExitCode {
+    Success = 0x10,
+    Failed = 0x11,
+}
+
+/// Exit using `isa-debug-exit`, for use in tests.
+///
+/// NOTE: This is a temporary mechanism until we get proper shutdown implemented.
+#[cfg(test)]
+pub(crate) fn qemu_exit(exit_code: QemuExitCode) -> ! {
+    let code = exit_code as u32;
+    unsafe {
+        asm!("out 0xf4, eax" :: "{eax}"(code) :: "intel","volatile");
+
+        // If the previous line didn't immediately trigger shutdown, hang.
+        asm!("cli" :::: "volatile");
+        loop {
+            asm!("hlt" :::: "volatile");
+        }
+    }
+}

src/lib.rs

@@ -1,19 +1,18 @@
+#![cfg_attr(all(target_os = "none", test), no_main)]
 #![cfg_attr(target_os = "none", no_std)]
 #![cfg_attr(target_os = "none", feature(alloc_error_handler))]
+#![cfg_attr(target_os = "none", feature(panic_info_message, track_caller))]
 #![feature(asm)]
+
 extern crate alloc;
 
 pub mod arch;
 
 use core::fmt::Write;
 use hal_core::{boot::BootInfo, mem};
 
-use alloc::vec::Vec;
-
 mod wasm;
 
-const HELLOWORLD_WASM: &[u8] = include_bytes!(concat!(env!("OUT_DIR"), "/helloworld.wasm"));
-
 pub fn kernel_main(bootinfo: &impl BootInfo) -> ! {
     let mut writer = bootinfo.writer();
     writeln!(
@@ -62,10 +61,44 @@ pub fn kernel_main(bootinfo: &impl BootInfo) -> ! {
 
     arch::interrupt::init::<arch::InterruptHandlers>();
 
+    #[cfg(test)]
     {
-        let span = tracing::info_span!("alloc test");
+        let span = tracing::info_span!("run tests");
         let _enter = span.enter();
+
+        let mut passed = 0;
+        let mut failed = 0;
+        for test in mycelium_util::testing::all_tests() {
+            let span = tracing::info_span!("test", test.name, test.module);
+            let _enter = span.enter();
+
+            if (test.run)() {
+                passed += 1;
+            } else {
+                failed += 1;
+            }
+        }
+
+        tracing::warn!("{} passed | {} failed", passed, failed);
+        if failed == 0 {
+            arch::qemu_exit(arch::QemuExitCode::Success);
+        } else {
+            arch::qemu_exit(arch::QemuExitCode::Failed);
+        }
+    }
+
+    // if this function returns we would boot loop. Hang, instead, so the debug
+    // output can be read.
+    //
+    // eventually we'll call into a kernel main loop here...
+    #[allow(clippy::empty_loop)]
+    loop {}
+}
+
+mycelium_util::decl_test! {
+    fn basic_alloc() {
         // Let's allocate something, for funsies
+        use alloc::vec::Vec;
         let mut v = Vec::new();
         tracing::info!(vec = ?v, vec.addr = ?v.as_ptr());
         v.push(5u64);
@@ -75,23 +108,13 @@ pub fn kernel_main(bootinfo: &impl BootInfo) -> ! {
         assert_eq!(v.pop(), Some(10));
         assert_eq!(v.pop(), Some(5));
     }
+}
 
-    {
-        let span = tracing::info_span!("wasm test");
-        let _enter = span.enter();
-
-        match wasm::run_wasm(HELLOWORLD_WASM) {
-            Ok(()) => tracing::info!("wasm test Ok!"),
-            Err(err) => tracing::error!(?err, "wasm test Err"),
-        }
+mycelium_util::decl_test! {
+    fn wasm_hello_world() -> Result<(), wasmi::Error> {
+        const HELLOWORLD_WASM: &[u8] = include_bytes!(concat!(env!("OUT_DIR"), "/helloworld.wasm"));
+        wasm::run_wasm(HELLOWORLD_WASM)
     }
-
-    // if this function returns we would boot loop. Hang, instead, so the debug
-    // output can be read.
-    //
-    // eventually we'll call into a kernel main loop here...
-    #[allow(clippy::empty_loop)]
-    loop {}
 }
 
 #[global_allocator]
@@ -103,3 +126,45 @@ pub static GLOBAL: mycelium_alloc::Alloc = mycelium_alloc::Alloc;
 fn alloc_error(layout: core::alloc::Layout) -> ! {
     panic!("alloc error: {:?}", layout);
 }
+
+#[cfg(target_os = "none")]
+#[panic_handler]
+#[cold]
+fn panic(panic: &core::panic::PanicInfo) -> ! {
+    use core::fmt;
+
+    struct PrettyPanic<'a>(&'a core::panic::PanicInfo<'a>);
+    impl<'a> fmt::Display for PrettyPanic<'a> {
+        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+            let message = self.0.message();
+            let location = self.0.location();
+            let caller = core::panic::Location::caller();
+            if let Some(message) = message {
+                writeln!(f, "  mycelium panicked: {}", message)?;
+                if let Some(loc) = location {
+                    writeln!(f, "  at: {}:{}:{}", loc.file(), loc.line(), loc.column(),)?;
+                }
+            } else {
+                writeln!(f, "  mycelium panicked: {}", self.0)?;
+            }
+            writeln!(
+                f,
+                "  in: {}:{}:{}",
+                caller.file(),
+                caller.line(),
+                caller.column()
+            )?;
+            Ok(())
+        }
+    }
+
+    let caller = core::panic::Location::caller();
+    tracing::error!(%panic, ?caller);
+    let pp = PrettyPanic(panic);
+    arch::oops(&pp)
+}
+
+#[cfg(all(test, not(target_os = "none")))]
+pub fn main() {
+    /* no host-platform tests in this crate */
+}

src/main.rs

@@ -3,47 +3,6 @@
 #![cfg_attr(target_os = "none", feature(alloc_error_handler))]
 #![cfg_attr(target_os = "none", feature(asm))]
 #![cfg_attr(target_os = "none", feature(panic_info_message, track_caller))]
-use mycelium_kernel::arch;
 
-#[cfg(target_os = "none")]
-#[panic_handler]
-#[cold]
-fn panic(panic: &core::panic::PanicInfo) -> ! {
-    use core::fmt;
-
-    struct PrettyPanic<'a>(&'a core::panic::PanicInfo<'a>);
-    impl<'a> fmt::Display for PrettyPanic<'a> {
-        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-            let message = self.0.message();
-            let location = self.0.location();
-            let caller = core::panic::Location::caller();
-            if let Some(message) = message {
-                writeln!(f, "  mycelium panicked: {}", message)?;
-                if let Some(loc) = location {
-                    writeln!(f, "  at: {}:{}:{}", loc.file(), loc.line(), loc.column(),)?;
-                }
-            } else {
-                writeln!(f, "  mycelium panicked: {}", self.0)?;
-            }
-            writeln!(
-                f,
-                "  in: {}:{}:{}",
-                caller.file(),
-                caller.line(),
-                caller.column()
-            )?;
-            Ok(())
-        }
-    }
-
-    let caller = core::panic::Location::caller();
-    tracing::error!(%panic, ?caller);
-    let pp = PrettyPanic(panic);
-    arch::oops(&pp)
-}
-
-fn main() {
-    unsafe {
-        core::hint::unreachable_unchecked();
-    }
-}
+// Force linking to the `mycelium_kernel` lib.
+use mycelium_kernel;

util/Cargo.toml

@@ -10,6 +10,7 @@ edition = "2018"
 alloc = []
 
 [dependencies]
+tracing = { version = "0.1", default_features = false }
 loom = { version = "0.2.14", optional = true }
 
 [dev-dependencies]