1 files changed, 52 insertions, 0 deletions
diff --git a/library/core/tests/iter/adapters/cloned.rs b/library/core/tests/iter/adapters/cloned.rs
new file mode 100644
index 000000000..78babb7fe
--- /dev/null
+++ b/library/core/tests/iter/adapters/cloned.rs
@@ -0,0 +1,52 @@
+use core::iter::*;
+
+#[test]
+fn test_cloned() {
+    let xs = [2, 4, 6, 8];
+
+    let mut it = xs.iter().cloned();
+    assert_eq!(it.len(), 4);
+    assert_eq!(it.next(), Some(2));
+    assert_eq!(it.len(), 3);
+    assert_eq!(it.next(), Some(4));
+    assert_eq!(it.len(), 2);
+    assert_eq!(it.next_back(), Some(8));
+    assert_eq!(it.len(), 1);
+    assert_eq!(it.next_back(), Some(6));
+    assert_eq!(it.len(), 0);
+    assert_eq!(it.next_back(), None);
+}
+
+#[test]
+fn test_cloned_side_effects() {
+    let mut count = 0;
+    {
+        let iter = [1, 2, 3]
+            .iter()
+            .map(|x| {
+                count += 1;
+                x
+            })
+            .cloned()
+            .zip(&[1]);
+        for _ in iter {}
+    }
+    assert_eq!(count, 2);
+}
+
+#[test]
+fn test_cloned_try_folds() {
+    let a = [1, 2, 3, 4, 5, 6, 7, 8, 9];
+    let f = &|acc, x| i32::checked_add(2 * acc, x);
+    let f_ref = &|acc, &x| i32::checked_add(2 * acc, x);
+    assert_eq!(a.iter().cloned().try_fold(7, f), a.iter().try_fold(7, f_ref));
+    assert_eq!(a.iter().cloned().try_rfold(7, f), a.iter().try_rfold(7, f_ref));
+
+    let a = [10, 20, 30, 40, 100, 60, 70, 80, 90];
+    let mut iter = a.iter().cloned();
+    assert_eq!(iter.try_fold(0_i8, |acc, x| acc.checked_add(x)), None);
+    assert_eq!(iter.next(), Some(60));
+    let mut iter = a.iter().cloned();
+    assert_eq!(iter.try_rfold(0_i8, |acc, x| acc.checked_add(x)), None);
+    assert_eq!(iter.next_back(), Some(70));
+}