fix: make code in doc runable

feat: add test from example

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

Author: woshiluo

src/de.rs

@@ -31,8 +31,17 @@ use serde::de;
 /// # Example
 ///
 /// ```
-/// # static DEVICE_TREE: &'static [u8] = include_bytes!("../examples/hifive-unmatched-a00.dtb");
-/// # let dtb_pa = DEVICE_TREE.as_ptr() as usize;
+/// # static RAW_DEVICE_TREE: &'static [u8] = include_bytes!("../examples/hifive-unmatched-a00.dtb");
+/// # const BUFFER_SIZE: usize = RAW_DEVICE_TREE.len();
+/// # #[repr(align(4))]
+/// # struct AlignedBuffer {
+/// #     pub data: [u8; RAW_DEVICE_TREE.len()],
+/// # }
+/// # 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 fdt_ptr = aligned_data.data.as_ptr();
 /// use serde_derive::Deserialize;
 ///
 /// #[derive(Debug, Deserialize)]
@@ -47,7 +56,7 @@ use serde::de;
 ///     stdout_path: Option<&'a str>,
 /// }
 ///
-/// let tree: Tree = unsafe { serde_device_tree::from_raw(dtb_pa as *const u8) }
+/// let tree: Tree = unsafe { serde_device_tree::from_raw(fdt_ptr as *const u8) }
 ///     .expect("parse device tree");
 /// if let Some(chosen) = tree.chosen {
 ///     if let Some(stdout_path) = chosen.stdout_path {

tests/hifive-unmatched-a00.rs

@@ -0,0 +1,59 @@
+use serde_derive::Deserialize;
+use serde_device_tree::Compatible;
+
+#[derive(Debug, Deserialize)]
+struct Tree<'a> {
+    #[serde(rename = "#address-cells")]
+    num_address_cells: u32,
+    #[serde(rename = "#size-cells")]
+    num_size_cells: u32,
+    model: &'a str,
+    #[allow(unused)]
+    compatible: Compatible<'a>,
+    chosen: Option<Chosen<'a>>,
+    cpus: Cpus,
+}
+
+#[derive(Debug, Deserialize)]
+#[serde(rename_all = "kebab-case")]
+struct Chosen<'a> {
+    stdout_path: Option<&'a str>,
+}
+
+#[derive(Debug, Deserialize)]
+#[serde(rename_all = "kebab-case")]
+struct Cpus {
+    timebase_frequency: u32,
+    #[serde(rename = "u-boot,dm-spl")]
+    u_boot_dm_spl: bool,
+}
+
+const RAW_DEVICE_TREE: &[u8] = include_bytes!("../examples/hifive-unmatched-a00.dtb");
+const BUFFER_SIZE: usize = RAW_DEVICE_TREE.len();
+
+#[repr(align(4))]
+struct AlignedBuffer {
+    pub data: [u8; RAW_DEVICE_TREE.len()],
+}
+
+#[test]
+fn hifive_unmatched() {
+    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 ptr = aligned_data.data.as_ptr();
+    let t: Tree = unsafe { serde_device_tree::from_raw(ptr) }.unwrap();
+    assert_eq!(t.num_address_cells, 2);
+    assert_eq!(t.num_size_cells, 2);
+    assert_eq!(t.model, "SiFive HiFive Unmatched A00\0");
+    if let Some(chosen) = t.chosen {
+        if let Some(stdout_path) = chosen.stdout_path {
+            assert_eq!(stdout_path, "serial0\0");
+        } else {
+            assert!(false, "Failed to find chosen/stdout_path");
+        }
+    }
+    assert_eq!(t.cpus.timebase_frequency, 1000000);
+    assert_eq!(t.cpus.u_boot_dm_spl, true);
+}