feat: add test from qemu-virt

Signed-off-by: Woshiluo Luo <woshiluo.luo@outlook.com>

Author: woshiluo

tests/qemu-virt.rs

@@ -0,0 +1,52 @@
+// 在实际使用中，将这里的 `serde_derive::Deserialize` 改为 `serde::Deserialize`。
+use serde_derive::Deserialize;
+
+use serde_device_tree::{
+    buildin::{NodeSeq, Reg},
+    error::Error,
+    from_raw_mut, Dtb, DtbPtr,
+};
+
+const RAW_DEVICE_TREE: &[u8] = include_bytes!("../examples/qemu-virt.dtb");
+const BUFFER_SIZE: usize = RAW_DEVICE_TREE.len();
+
+#[repr(align(8))]
+struct AlignedBuffer {
+    pub data: [u8; RAW_DEVICE_TREE.len()],
+}
+
+#[derive(Deserialize)]
+struct Tree<'a> {
+    soc: Soc<'a>,
+}
+
+#[allow(dead_code)]
+#[derive(Deserialize)]
+struct Soc<'a> {
+    virtio_mmio: NodeSeq<'a>,
+}
+
+#[derive(Deserialize)]
+#[allow(unused)]
+struct VirtIoMmio<'a> {
+    reg: Reg<'a>,
+}
+
+#[test]
+fn qemu_virt() -> Result<(), Error> {
+    // 整个设备树二进制文件需要装载到一块可写的内存区域
+    let mut aligned_data: Box<AlignedBuffer> = Box::new(AlignedBuffer {
+        data: [0; BUFFER_SIZE],
+    });
+    aligned_data.data[..BUFFER_SIZE].clone_from_slice(RAW_DEVICE_TREE);
+    let mut slice = aligned_data.data.to_vec();
+    let ptr = DtbPtr::from_raw(slice.as_mut_ptr())?;
+    let dtb = Dtb::from(ptr).share();
+
+    let t: Tree = from_raw_mut(&dtb).unwrap();
+
+    assert_eq!(t.soc.virtio_mmio.len(), 8);
+    assert_eq!(slice, RAW_DEVICE_TREE);
+
+    Ok(())
+}