Update tests3.rs

Author: 13001288072

exercises/tests/tests3.rs

@@ -1,14 +1,3 @@
-// tests3.rs
-//
-// This test isn't testing our function -- make it do that in such a way that
-// the test passes. Then write a second test that tests whether we get the
-// result we expect to get when we call `is_even(5)`.
-//
-// Execute `rustlings hint tests3` or use the `hint` watch subcommand for a
-// hint.
-
-// I AM NOT DONE
-
 pub fn is_even(num: i32) -> bool {
     num % 2 == 0
 }
@@ -19,11 +8,13 @@ mod tests {
 
     #[test]
     fn is_true_when_even() {
-        assert!();
+        // 测试偶数：调用is_even(4)应该返回true，assert!验证条件为真
+        assert!(is_even(4));
     }
 
     #[test]
     fn is_false_when_odd() {
-        assert!();
+        // 测试奇数：调用is_even(5)应该返回false，assert!验证条件为假（加!取反）
+        assert!(!is_even(5));
     }
 }