minor refactoring

tests/test_data.rs

@@ -1,8 +1,7 @@
-use std::mem::offset_of;
-use x::win32::ImageOptionalHeader64;
+
 
 #[test]
-pub fn test_distance() {
+pub fn test_data() {
     let _ = x::dur![ 5 days 4 hours 7 minutes 2 seconds 2 minutes ];
 
     let a = [0u8, 2, 3];
@@ -27,4 +26,12 @@ pub fn test_distance() {
         x::iterate(b).cloned().take_while(|&c| c != 0))
         .filter_map(|_r| _r.ok()).collect();
     assert_eq!("Hello World", hello_world);
+
+    test1(x::null());
+    test2(x::null());
+
 }
+
+
+fn test1(_a: *const u8) {}
+fn test2(_a: *mut u8) {}