std: sys: pal: uefi: tests: Add systemtime tests

Add tests to ensure that extream system times are still representable.

Signed-off-by: Ayush Singh <[email protected]>

Author: Ayush1325

library/std/src/sys/pal/uefi/tests.rs

@@ -1,4 +1,8 @@
 use super::alloc::*;
+use super::time::system_time_internal::{from_uefi, to_uefi};
+use crate::time::Duration;
+
+const SECS_IN_MINUTE: u64 = 60;
 
 #[test]
 fn align() {
@@ -19,3 +23,62 @@ fn align() {
         }
     }
 }
+
+#[test]
+fn systemtime_start() {
+    let t = r_efi::efi::Time {
+        year: 1900,
+        month: 1,
+        day: 1,
+        hour: 0,
+        minute: 0,
+        second: 0,
+        pad1: 0,
+        nanosecond: 0,
+        timezone: -1440,
+        daylight: 0,
+        pad2: 0,
+    };
+    assert_eq!(from_uefi(&t), Duration::new(0, 0));
+    assert_eq!(t, to_uefi(&from_uefi(&t), -1440, 0).unwrap());
+    assert!(to_uefi(&from_uefi(&t), 0, 0).is_none());
+}
+
+#[test]
+fn systemtime_utc_start() {
+    let t = r_efi::efi::Time {
+        year: 1900,
+        month: 1,
+        day: 1,
+        hour: 0,
+        minute: 0,
+        second: 0,
+        pad1: 0,
+        nanosecond: 0,
+        timezone: 0,
+        daylight: 0,
+        pad2: 0,
+    };
+    assert_eq!(from_uefi(&t), Duration::new(1440 * SECS_IN_MINUTE, 0));
+    assert_eq!(t, to_uefi(&from_uefi(&t), 0, 0).unwrap());
+    assert!(to_uefi(&from_uefi(&t), -1440, 0).is_some());
+}
+
+#[test]
+fn systemtime_end() {
+    let t = r_efi::efi::Time {
+        year: 9999,
+        month: 12,
+        day: 31,
+        hour: 23,
+        minute: 59,
+        second: 59,
+        pad1: 0,
+        nanosecond: 0,
+        timezone: 1440,
+        daylight: 0,
+        pad2: 0,
+    };
+    assert!(to_uefi(&from_uefi(&t), 1440, 0).is_some());
+    assert!(to_uefi(&from_uefi(&t), 1439, 0).is_none());
+}