fix(core): fix split_off operation for RrbVec

src/core/mod.rs

@@ -345,6 +345,9 @@ impl<T: Clone + Debug> RrbVec<T> {
 
                         right.tail = new_tail;
                         right.tail_len = new_tail_len;
+
+                        // in case if tail is exactly BRANCH_FACTOR long, we should push it to the tree
+                        right.push_tail()
                     } else if right.tree.len() < BRANCH_FACTOR {
                         // root is leaf, but it is not fully dense
                         // hence, some of the values should be redistributed to the actual leaf

tests/tests.rs

@@ -265,6 +265,21 @@ macro_rules! make_tests {
                 }
             }
 
+            #[test]
+            fn interleaving_push_split_off_push_operations() {
+                let mut vec_one = $vec::new();
+
+                for i in 0..(BRANCH_FACTOR * BRANCH_FACTOR) {
+                    vec_one.push(i);
+                }
+
+                let mut vec_two = vec_one.split_off(BRANCH_FACTOR * BRANCH_FACTOR - BRANCH_FACTOR);
+                vec_two.push(0xbeef);
+
+                assert_eq!(vec_one.len(), BRANCH_FACTOR * BRANCH_FACTOR - BRANCH_FACTOR);
+                assert_eq!(vec_two.len(), BRANCH_FACTOR + 1);
+            }
+
             #[test]
             fn interleaving_different_operations_must_maintain_correct_internal_state_for_var_sizes_4() {
                 interleaving_different_operations_must_maintain_correct_internal_state(4);