add single file tests

single_file_tests/time.rs

@@ -0,0 +1,26 @@
+use std::time::SystemTime;
+
+fn get_year_and_left_secs(secs_from_1970: u64) -> (u32, u64) {
+    let mut t = secs_from_1970;
+    let mut y = 1970;
+    loop {
+        let is_leap_year = y % 4 == 0 && y % 100 != 0;
+        let secs_per_year = if is_leap_year { 366 } else { 365 } * 24 * 60 * 60;
+        if t > secs_per_year {
+            y += 1;
+            t -= secs_per_year;
+        } else {
+            return (y, t);
+        }
+    }
+}
+
+fn main() {
+    let secs_from_1970 = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
+    let (year_gmt, _) = get_year_and_left_secs(secs_from_1970);
+    let (year_gmt8, _) = get_year_and_left_secs(secs_from_1970 + 8 * 60 * 60);
+
+    println!("Secs from 1970: {}", secs_from_1970);
+    println!("Year (GMT)    : {}", year_gmt);
+    println!("Year (GMT+8)  : {}", year_gmt8);
+}