1 files changed, 9 insertions, 5 deletions
diff --git a/library/core/tests/iter/adapters/skip.rs b/library/core/tests/iter/adapters/skip.rs
index 754641834..e3e88a84f 100644
--- a/library/core/tests/iter/adapters/skip.rs
+++ b/library/core/tests/iter/adapters/skip.rs
@@ -1,4 +1,5 @@
 use core::iter::*;
+use core::num::NonZeroUsize;
 
 use super::Unfuse;
 
@@ -74,11 +75,14 @@ fn test_iterator_skip_nth() {
 #[test]
 fn test_skip_advance_by() {
     assert_eq!((0..0).skip(10).advance_by(0), Ok(()));
-    assert_eq!((0..0).skip(10).advance_by(1), Err(0));
-    assert_eq!((0u128..(usize::MAX as u128) + 1).skip(usize::MAX).advance_by(usize::MAX), Err(1));
-    assert_eq!((0u128..u128::MAX).skip(usize::MAX).advance_by(1), Ok(()));
-
-    assert_eq!((0..2).skip(1).advance_back_by(10), Err(1));
+    assert_eq!((0..0).skip(10).advance_by(1), Err(NonZeroUsize::new(1).unwrap()));
+    assert_eq!(
+        (0u128..(usize::MAX as u128) + 1).skip(usize::MAX - 10).advance_by(usize::MAX - 5),
+        Err(NonZeroUsize::new(usize::MAX - 16).unwrap())
+    );
+    assert_eq!((0u128..u128::MAX).skip(usize::MAX - 10).advance_by(20), Ok(()));
+
+    assert_eq!((0..2).skip(1).advance_back_by(10), Err(NonZeroUsize::new(9).unwrap()));
     assert_eq!((0..0).skip(1).advance_back_by(0), Ok(()));
 }