add tests

Author: BenjaminBrienen

library/alloc/src/vec/mod.rs

@@ -2236,14 +2236,12 @@ impl<T, A: Allocator> Vec<T, A> {
     /// # Examples
     ///
     /// ```
-    /// let mut v = vec!['a', 'b', 'c'];
-    /// assert_eq!(v.try_remove(1), Some('b'));
-    /// assert_eq!(v, ['a', 'c']);
-    ///
+    /// #![feature(vec_try_remove)]
+    /// let mut v = vec![1, 2, 3];
+    /// assert_eq!(v.try_remove(0), Some(1));
     /// assert_eq!(v.try_remove(2), None);
-    /// assert_eq!(v, ['a', 'c']);
     /// ```
-    #[stable(feature = "vec_try_remove", since = "1.92.0")]
+    #[unstable(feature = "vec_try_remove", issue = "77481")]
     #[track_caller]
     #[rustc_confusables("delete", "take", "remove")]
     pub fn try_remove(&mut self, index: usize) -> Option<T> {

library/alloctests/tests/lib.rs

@@ -42,6 +42,7 @@
 #![feature(unique_rc_arc)]
 #![feature(macro_metavar_expr_concat)]
 #![feature(vec_peek_mut)]
+#![feature(vec_try_remove)]
 #![allow(internal_features)]
 #![deny(fuzzy_provenance_casts)]
 #![deny(unsafe_op_in_unsafe_fn)]

library/alloctests/tests/vec.rs

@@ -630,6 +630,21 @@ fn test_swap_remove_empty() {
     vec.swap_remove(0);
 }
 
+#[test]
+fn test_try_remove() {
+    let mut vec = vec![1, 2, 3];
+    // We are attempting to remove vec[0] which contains 1
+    assert_eq!(vec.try_remove(0), Some(1));
+    // Now `vec` looks like: [2, 3]
+    // We will now try to remove vec[2] which does not exist
+    // This should return `None`
+    assert_eq!(vec.try_remove(2), None);
+
+    // We will try the same thing with an empty vector
+    let mut v: Vec<u8> = vec![];
+    assert!(v.try_remove(0).is_none());
+}
+
 #[test]
 fn test_move_items() {
     let vec = vec![1, 2, 3];