From ffeac1f71fe8d8206c9c83747cdd7816ad9aafc2 Mon Sep 17 00:00:00 2001
From: Stein Somers <git@steinsomers.be>
Date: Sun, 20 Oct 2019 20:06:20 +0200
Subject: proposal for access to BTreeMap/BTreeSet first/last, #62924

---
 src/liballoc/tests/btree/map.rs | 45 +++++++++++++++++++++++++++++++++++++++++
 src/liballoc/tests/btree/set.rs | 28 +++++++++++++++++++++++++
 src/liballoc/tests/lib.rs       |  1 +
 3 files changed, 74 insertions(+)

(limited to 'src/liballoc/tests')

diff --git a/src/liballoc/tests/btree/map.rs b/src/liballoc/tests/btree/map.rs
index 266a0d055d5..27843aeaeb0 100644
--- a/src/liballoc/tests/btree/map.rs
+++ b/src/liballoc/tests/btree/map.rs
@@ -58,15 +58,35 @@ fn test_basic_large() {
 fn test_basic_small() {
     let mut map = BTreeMap::new();
     assert_eq!(map.remove(&1), None);
+    assert_eq!(map.len(), 0);
+    assert_eq!(map.first_key_value(), None);
+    assert_eq!(map.last_key_value(), None);
     assert_eq!(map.get(&1), None);
     assert_eq!(map.insert(1, 1), None);
+    assert_eq!(map.len(), 1);
     assert_eq!(map.get(&1), Some(&1));
+    assert_eq!(map.first_key_value(), Some((&1, &1)));
+    assert_eq!(map.last_key_value(), Some((&1, &1)));
     assert_eq!(map.insert(1, 2), Some(1));
+    assert_eq!(map.len(), 1);
     assert_eq!(map.get(&1), Some(&2));
+    assert_eq!(map.first_key_value(), Some((&1, &2)));
+    assert_eq!(map.last_key_value(), Some((&1, &2)));
     assert_eq!(map.insert(2, 4), None);
+    assert_eq!(map.len(), 2);
     assert_eq!(map.get(&2), Some(&4));
+    assert_eq!(map.first_key_value(), Some((&1, &2)));
+    assert_eq!(map.last_key_value(), Some((&2, &4)));
     assert_eq!(map.remove(&1), Some(2));
+    assert_eq!(map.len(), 1);
+    assert_eq!(map.get(&1), None);
+    assert_eq!(map.get(&2), Some(&4));
+    assert_eq!(map.first_key_value(), Some((&2, &4)));
+    assert_eq!(map.last_key_value(), Some((&2, &4)));
     assert_eq!(map.remove(&2), Some(4));
+    assert_eq!(map.len(), 0);
+    assert_eq!(map.first_key_value(), None);
+    assert_eq!(map.last_key_value(), None);
     assert_eq!(map.remove(&1), None);
 }
 
@@ -605,6 +625,31 @@ fn test_vacant_entry_key() {
     assert_eq!(a[key], value);
 }
 
+#[test]
+fn test_first_last_entry() {
+    let mut a = BTreeMap::new();
+    assert!(a.first_entry().is_none());
+    assert!(a.last_entry().is_none());
+    a.insert(1, 42);
+    assert_eq!(a.first_entry().unwrap().key(), &1);
+    assert_eq!(a.last_entry().unwrap().key(), &1);
+    a.insert(2, 24);
+    assert_eq!(a.first_entry().unwrap().key(), &1);
+    assert_eq!(a.last_entry().unwrap().key(), &2);
+    a.insert(0, 6);
+    assert_eq!(a.first_entry().unwrap().key(), &0);
+    assert_eq!(a.last_entry().unwrap().key(), &2);
+    let (k1, v1) = a.first_entry().unwrap().remove_entry();
+    assert_eq!(k1, 0);
+    assert_eq!(v1, 6);
+    let (k2, v2) = a.last_entry().unwrap().remove_entry();
+    assert_eq!(k2, 2);
+    assert_eq!(v2, 24);
+    assert_eq!(a.first_entry().unwrap().key(), &1);
+    assert_eq!(a.last_entry().unwrap().key(), &1);
+}
+
+
 macro_rules! create_append_test {
     ($name:ident, $len:expr) => {
         #[test]
diff --git a/src/liballoc/tests/btree/set.rs b/src/liballoc/tests/btree/set.rs
index e4883abc8b5..13cd2628022 100644
--- a/src/liballoc/tests/btree/set.rs
+++ b/src/liballoc/tests/btree/set.rs
@@ -470,6 +470,34 @@ fn test_append() {
     assert_eq!(a.contains(&5), true);
 }
 
+#[test]
+fn test_first_last() {
+    let mut a = BTreeSet::new();
+    assert_eq!(a.first(), None);
+    assert_eq!(a.last(), None);
+    a.insert(1);
+    assert_eq!(a.first(), Some(&1));
+    assert_eq!(a.last(), Some(&1));
+    a.insert(2);
+    assert_eq!(a.first(), Some(&1));
+    assert_eq!(a.last(), Some(&2));
+    a.insert(3);
+    assert_eq!(a.first(), Some(&1));
+    assert_eq!(a.last(), Some(&3));
+
+    assert_eq!(a.len(), 3);
+    assert_eq!(a.pop_first(), Some(1));
+    assert_eq!(a.len(), 2);
+    assert_eq!(a.pop_last(), Some(3));
+    assert_eq!(a.len(), 1);
+    assert_eq!(a.pop_first(), Some(2));
+    assert_eq!(a.len(), 0);
+    assert_eq!(a.pop_last(), None);
+    assert_eq!(a.len(), 0);
+    assert_eq!(a.pop_first(), None);
+    assert_eq!(a.len(), 0);
+}
+
 fn rand_data(len: usize) -> Vec<u32> {
     let mut rng = DeterministicRng::new();
     Vec::from_iter((0..len).map(|_| rng.next()))
diff --git a/src/liballoc/tests/lib.rs b/src/liballoc/tests/lib.rs
index 676874c8b27..ea0f76174e4 100644
--- a/src/liballoc/tests/lib.rs
+++ b/src/liballoc/tests/lib.rs
@@ -2,6 +2,7 @@
 #![feature(box_syntax)]
 #![feature(drain_filter)]
 #![feature(exact_size_is_empty)]
+#![feature(map_first_last)]
 #![feature(new_uninit)]
 #![feature(option_flattening)]
 #![feature(pattern)]
-- 
cgit 1.4.1-3-g733a5