Implement nth_back for RChunks(Exact)(Mut)

1 files changed, 52 insertions, 0 deletions

diff --git a/src/libcore/tests/slice.rs b/src/libcore/tests/slice.rs
index acf6b03791f..cd520a052a0 100644
--- a/src/libcore/tests/slice.rs
+++ b/src/libcore/tests/slice.rs
@@ -357,6 +357,19 @@ fn test_rchunks_nth() {
 }
 
 #[test]
+fn test_rchunks_nth_back() {
+    let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+    let mut c = v.rchunks(2);
+    assert_eq!(c.nth_back(1).unwrap(), &[2, 3]);
+    assert_eq!(c.next_back().unwrap(), &[4, 5]);
+
+    let v2: &[i32] = &[0, 1, 2, 3, 4];
+    let mut c2 = v2.rchunks(3);
+    assert_eq!(c2.nth_back(1).unwrap(), &[2, 3, 4]);
+    assert_eq!(c2.next_back(), None);
+}
+
+#[test]
 fn test_rchunks_last() {
     let v: &[i32] = &[0, 1, 2, 3, 4, 5];
     let c = v.rchunks(2);
@@ -408,6 +421,19 @@ fn test_rchunks_mut_nth() {
 }
 
 #[test]
+fn test_rchunks_mut_nth_back() {
+    let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
+    let mut c = v.rchunks_mut(2);
+    assert_eq!(c.nth_back(1).unwrap(), &[2, 3]);
+    assert_eq!(c.next_back().unwrap(), &[4, 5]);
+
+    let v2: &mut [i32] = &mut [0, 1, 2, 3, 4];
+    let mut c2 = v2.rchunks_mut(3);
+    assert_eq!(c2.nth_back(1).unwrap(), &[2, 3, 4]);
+    assert_eq!(c2.next_back(), None);
+}
+
+#[test]
 fn test_rchunks_mut_last() {
     let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
     let c = v.rchunks_mut(2);
@@ -461,6 +487,19 @@ fn test_rchunks_exact_nth() {
 }
 
 #[test]
+fn test_rchunks_exact_nth_back() {
+    let v: &[i32] = &[0, 1, 2, 3, 4, 5];
+    let mut c = v.rchunks_exact(2);
+    assert_eq!(c.nth_back(1).unwrap(), &[2, 3]);
+    assert_eq!(c.next_back().unwrap(), &[4, 5]);
+
+    let v2: &[i32] = &[0, 1, 2, 3, 4, 5, 6];
+    let mut c2 = v2.rchunks_exact(3);
+    assert_eq!(c2.nth_back(1).unwrap(), &[4, 5, 6]);
+    assert_eq!(c2.next(), None);
+}
+
+#[test]
 fn test_rchunks_exact_last() {
     let v: &[i32] = &[0, 1, 2, 3, 4, 5];
     let c = v.rchunks_exact(2);
@@ -519,6 +558,19 @@ fn test_rchunks_exact_mut_nth() {
 }
 
 #[test]
+fn test_rchunks_exact_mut_nth_back() {
+    let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
+    let mut c = v.rchunks_exact_mut(2);
+    assert_eq!(c.nth_back(1).unwrap(), &[2, 3]);
+    assert_eq!(c.next_back().unwrap(), &[4, 5]);
+
+    let v2: &mut [i32] = &mut [0, 1, 2, 3, 4, 5, 6];
+    let mut c2 = v2.rchunks_exact_mut(3);
+    assert_eq!(c2.nth_back(1).unwrap(), &[4, 5, 6]);
+    assert_eq!(c2.next(), None);
+}
+
+#[test]
 fn test_rchunks_exact_mut_last() {
     let v: &mut [i32] = &mut [0, 1, 2, 3, 4, 5];
     let c = v.rchunks_exact_mut(2);