empty_has_height_0

src/rstd/collections/tree.rs

@@ -231,3 +231,29 @@ impl<'a, Ctx: Context<'a>, A: MentionableBase<'a> + Clone> Clone for Tree<'a, Ct
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use std::convert::Infallible;
+
+    use crate::{
+        flow::{binary::*, comparator::*},
+        rstd::atomic_object::*,
+        testing::TestContextPlain,
+    };
+
+    use super::context::*;
+
+    type Trees =
+        TreeContext2<'static, TestContextPlain, AtomicObject<u64>, DefaultComparator, Infallible>;
+
+    fn new_trees() -> Trees {
+        Trees::new((DefaultComparator.into(), u64::f()))
+    }
+
+    #[test]
+    fn empty_has_height_0() {
+        let trees = new_trees();
+        assert_eq!(trees.height(&trees.empty()), 0);
+    }
+}

src/rstd/collections/tree/context.rs

@@ -15,8 +15,8 @@ use super::*;
 pub struct TreeContext<Cl, T>(Cl, PhantomData<T>);
 
 impl<Cl: Clone, T> TreeContext<Cl, T> {
-    fn new(comparator: Cl) -> Self {
+    pub fn new(cl: Cl) -> Self {
-        Self(comparator, PhantomData)
+        Self(cl, PhantomData)
     }
 }