Merge pull request #113 from gwilymk/add-test-for-rust-bug

Add test that data_end is in the correct place

agb/src/agb_alloc/bump_allocator.rs

@@ -3,16 +3,6 @@ use core::ptr::NonNull;
 
 use crate::interrupt::Mutex;
 
-fn get_data_end() -> usize {
-    extern "C" {
-        static __ewram_data_end: usize;
-    }
-
-    // TODO: This seems completely wrong, but without the &, rust generates
-    // a double dereference :/. Maybe a bug in nightly?
-    (unsafe { &__ewram_data_end }) as *const _ as usize
-}
-
 pub(crate) struct BumpAllocator {
     current_ptr: Mutex<Option<NonNull<u8>>>,
 }
@@ -60,3 +50,28 @@ unsafe impl GlobalAlloc for BumpAllocator {
 
     unsafe fn dealloc(&self, _ptr: *mut u8, _layout: Layout) {}
 }
+
+fn get_data_end() -> usize {
+    extern "C" {
+        static __ewram_data_end: usize;
+    }
+
+    // TODO: This seems completely wrong, but without the &, rust generates
+    // a double dereference :/. Maybe a bug in nightly?
+    (unsafe { &__ewram_data_end }) as *const _ as usize
+}
+
+#[test_case]
+fn should_return_data_end_somewhere_in_ewram(_gba: &mut crate::Gba) {
+    let data_end = get_data_end();
+
+    assert!(
+        0x0200_0000 <= data_end,
+        "data end should be bigger than 0x0200_0000, got {}",
+        data_end
+    );
+    assert!(
+        0x0204_0000 > data_end,
+        "data end should be smaller than 0x0203_0000"
+    );
+}