tests: add simple test case for ARM64 Image loader

The test_image.bin is a cut of the first 4096 bytes of a pre-compiled
linux kernel ARM64 Image. You can generate by:

	make Image
	head -c 4096 arch/arm64/boot/Image > test_image.bin

Signed-off-by: Qiu Wenbo <qiuwenbo@phytium.com.cn>

Author: crab2313

src/loader/mod.rs

@@ -519,8 +519,6 @@ impl KernelLoader for Image {
 #[cfg(test)]
 mod test {
     use super::*;
-    #[cfg(any(feature = "elf", feature = "bzimage"))]
-    #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
     use std::io::Cursor;
     use vm_memory::{Address, GuestAddress, GuestMemoryMmap};
 
@@ -547,6 +545,15 @@ mod test {
         v
     }
 
+    // first 4096 bytes of a precompiled ARM64 kernel Image.
+    #[cfg(feature = "image")]
+    #[cfg(target_arch = "aarch64")]
+    fn make_image_bin() -> Vec<u8> {
+        let mut v = Vec::new();
+        v.extend_from_slice(include_bytes!("test_image.bin"));
+        v
+    }
+
     #[allow(safe_packed_borrows)]
     #[allow(non_snake_case)]
     #[test]
@@ -669,6 +676,24 @@ mod test {
         );
     }
 
+    #[test]
+    #[cfg(feature = "image")]
+    #[cfg(target_arch = "aarch64")]
+    fn load_image() {
+        let gm = create_guest_mem();
+        let mut image = make_image_bin();
+        let kernel_addr = GuestAddress(0x200000);
+
+        let loader_result =
+            Image::load(&gm, Some(kernel_addr), &mut Cursor::new(&image), None).unwrap();
+        assert_eq!(loader_result.kernel_load.raw_value(), 0x280000);
+        assert_eq!(loader_result.kernel_end, 0x281000);
+
+        image[0x39] = 0x0;
+        let loader_result = Image::load(&gm, Some(kernel_addr), &mut Cursor::new(&image), None);
+        assert_eq!(loader_result, Err(Error::InvalidImageMagicNumber));
+    }
+
     #[test]
     fn cmdline_overflow() {
         let gm = create_guest_mem();