From 2a999b4b525ed8b4f735e233cc065b292d3eeb03 Mon Sep 17 00:00:00 2001
From: Joshua Liebow-Feeser <joshlf@google.com>
Date: Sat, 9 Jun 2018 22:32:05 -0700
Subject: Add Ref/RefMut map_split method

---
 src/libcore/tests/cell.rs | 58 +++++++++++++++++++++++++++++++++++++++++++++++
 src/libcore/tests/lib.rs  |  1 +
 2 files changed, 59 insertions(+)

(limited to 'src/libcore/tests')

diff --git a/src/libcore/tests/cell.rs b/src/libcore/tests/cell.rs
index 962fb2f0e02..4b7243b9cfc 100644
--- a/src/libcore/tests/cell.rs
+++ b/src/libcore/tests/cell.rs
@@ -165,6 +165,64 @@ fn ref_map_does_not_update_flag() {
     assert!(x.try_borrow_mut().is_ok());
 }
 
+#[test]
+fn ref_map_split_updates_flag() {
+    let x = RefCell::new([1, 2]);
+    {
+        let b1 = x.borrow();
+        assert!(x.try_borrow().is_ok());
+        assert!(x.try_borrow_mut().is_err());
+        {
+            let (_b2, _b3) = Ref::map_split(b1, |slc| slc.split_at(1));
+            assert!(x.try_borrow().is_ok());
+            assert!(x.try_borrow_mut().is_err());
+        }
+        assert!(x.try_borrow().is_ok());
+        assert!(x.try_borrow_mut().is_ok());
+    }
+    assert!(x.try_borrow().is_ok());
+    assert!(x.try_borrow_mut().is_ok());
+
+    {
+        let b1 = x.borrow_mut();
+        assert!(x.try_borrow().is_err());
+        assert!(x.try_borrow_mut().is_err());
+        {
+            let (_b2, _b3) = RefMut::map_split(b1, |slc| slc.split_at_mut(1));
+            assert!(x.try_borrow().is_err());
+            assert!(x.try_borrow_mut().is_err());
+            drop(_b2);
+            assert!(x.try_borrow().is_err());
+            assert!(x.try_borrow_mut().is_err());
+        }
+        assert!(x.try_borrow().is_ok());
+        assert!(x.try_borrow_mut().is_ok());
+    }
+    assert!(x.try_borrow().is_ok());
+    assert!(x.try_borrow_mut().is_ok());
+}
+
+#[test]
+fn ref_map_split() {
+    let x = RefCell::new([1, 2]);
+    let (b1, b2) = Ref::map_split(x.borrow(), |slc| slc.split_at(1));
+    assert_eq!(*b1, [1]);
+    assert_eq!(*b2, [2]);
+}
+
+#[test]
+fn ref_mut_map_split() {
+    let x = RefCell::new([1, 2]);
+    {
+        let (mut b1, mut b2) = RefMut::map_split(x.borrow_mut(), |slc| slc.split_at_mut(1));
+        assert_eq!(*b1, [1]);
+        assert_eq!(*b2, [2]);
+        b1[0] = 2;
+        b2[0] = 1;
+    }
+    assert_eq!(*x.borrow(), [2, 1]);
+}
+
 #[test]
 fn ref_map_accessor() {
     struct X(RefCell<(u32, char)>);
diff --git a/src/libcore/tests/lib.rs b/src/libcore/tests/lib.rs
index 13189d532ab..6d60010cca6 100644
--- a/src/libcore/tests/lib.rs
+++ b/src/libcore/tests/lib.rs
@@ -29,6 +29,7 @@
 #![feature(pattern)]
 #![feature(range_is_empty)]
 #![feature(raw)]
+#![feature(refcell_map_split)]
 #![feature(refcell_replace_swap)]
 #![feature(slice_patterns)]
 #![feature(slice_rotate)]
-- 
cgit 1.4.1-3-g733a5