1 files changed, 108 insertions, 0 deletions
diff --git a/library/core/tests/iter/sources.rs b/library/core/tests/iter/sources.rs
new file mode 100644
index 000000000..d0114ade6
--- /dev/null
+++ b/library/core/tests/iter/sources.rs
@@ -0,0 +1,108 @@
+use super::*;
+use core::iter::*;
+
+#[test]
+fn test_repeat() {
+    let mut it = repeat(42);
+    assert_eq!(it.next(), Some(42));
+    assert_eq!(it.next(), Some(42));
+    assert_eq!(it.next(), Some(42));
+    assert_eq!(repeat(42).size_hint(), (usize::MAX, None));
+}
+
+#[test]
+fn test_repeat_take() {
+    let mut it = repeat(42).take(3);
+    assert_eq!(it.next(), Some(42));
+    assert_eq!(it.next(), Some(42));
+    assert_eq!(it.next(), Some(42));
+    assert_eq!(it.next(), None);
+    is_trusted_len(repeat(42).take(3));
+    assert_eq!(repeat(42).take(3).size_hint(), (3, Some(3)));
+    assert_eq!(repeat(42).take(0).size_hint(), (0, Some(0)));
+    assert_eq!(repeat(42).take(usize::MAX).size_hint(), (usize::MAX, Some(usize::MAX)));
+}
+
+#[test]
+fn test_repeat_take_collect() {
+    let v: Vec<_> = repeat(42).take(3).collect();
+    assert_eq!(v, vec![42, 42, 42]);
+}
+
+#[test]
+fn test_repeat_with() {
+    #[derive(PartialEq, Debug)]
+    struct NotClone(usize);
+    let mut it = repeat_with(|| NotClone(42));
+    assert_eq!(it.next(), Some(NotClone(42)));
+    assert_eq!(it.next(), Some(NotClone(42)));
+    assert_eq!(it.next(), Some(NotClone(42)));
+    assert_eq!(repeat_with(|| NotClone(42)).size_hint(), (usize::MAX, None));
+}
+
+#[test]
+fn test_repeat_with_take() {
+    let mut it = repeat_with(|| 42).take(3);
+    assert_eq!(it.next(), Some(42));
+    assert_eq!(it.next(), Some(42));
+    assert_eq!(it.next(), Some(42));
+    assert_eq!(it.next(), None);
+    is_trusted_len(repeat_with(|| 42).take(3));
+    assert_eq!(repeat_with(|| 42).take(3).size_hint(), (3, Some(3)));
+    assert_eq!(repeat_with(|| 42).take(0).size_hint(), (0, Some(0)));
+    assert_eq!(repeat_with(|| 42).take(usize::MAX).size_hint(), (usize::MAX, Some(usize::MAX)));
+}
+
+#[test]
+fn test_repeat_with_take_collect() {
+    let mut curr = 1;
+    let v: Vec<_> = repeat_with(|| {
+        let tmp = curr;
+        curr *= 2;
+        tmp
+    })
+    .take(5)
+    .collect();
+    assert_eq!(v, vec![1, 2, 4, 8, 16]);
+}
+
+#[test]
+fn test_successors() {
+    let mut powers_of_10 = successors(Some(1_u16), |n| n.checked_mul(10));
+    assert_eq!(powers_of_10.by_ref().collect::<Vec<_>>(), &[1, 10, 100, 1_000, 10_000]);
+    assert_eq!(powers_of_10.next(), None);
+
+    let mut empty = successors(None::<u32>, |_| unimplemented!());
+    assert_eq!(empty.next(), None);
+    assert_eq!(empty.next(), None);
+}
+
+#[test]
+fn test_once() {
+    let mut it = once(42);
+    assert_eq!(it.next(), Some(42));
+    assert_eq!(it.next(), None);
+}
+
+#[test]
+fn test_once_with() {
+    let count = Cell::new(0);
+    let mut it = once_with(|| {
+        count.set(count.get() + 1);
+        42
+    });
+
+    assert_eq!(count.get(), 0);
+    assert_eq!(it.next(), Some(42));
+    assert_eq!(count.get(), 1);
+    assert_eq!(it.next(), None);
+    assert_eq!(count.get(), 1);
+    assert_eq!(it.next(), None);
+    assert_eq!(count.get(), 1);
+}
+
+#[test]
+fn test_empty() {
+    let mut it = empty::<i32>();
+    assert_eq!(it.next(), None);
+}