avl test

src/flow/binary/avl.rs

@@ -26,6 +26,14 @@ impl<A: Display> Display for AvlN<A> {
     }
 }
 
+#[cfg(test)]
+impl<A> AvlN<A> {
+    fn balanced(&self) -> bool {
+        let (lh, rh) = (self.l.height, self.r.height);
+        std::cmp::max(lh, rh) - std::cmp::min(lh, rh) < 2 && self.l.balanced() && self.r.balanced()
+    }
+}
+
 struct AvlR<A> {
     node: Rc<AvlN<A>>,
 }
@@ -44,6 +52,13 @@ impl<A: Display> Display for AvlR<A> {
     }
 }
 
+#[cfg(test)]
+impl<A> AvlR<A> {
+    fn balanced(&self) -> bool {
+        self.node.balanced()
+    }
+}
+
 struct AvlT<A> {
     reference: Option<AvlR<A>>,
     height: u64,
@@ -67,6 +82,16 @@ impl<A: Display> Display for AvlT<A> {
     }
 }
 
+#[cfg(test)]
+impl<A> AvlT<A> {
+    fn balanced(&self) -> bool {
+        match &self.reference {
+            Some(reference) => reference.balanced(),
+            None => true,
+        }
+    }
+}
+
 struct AvlTs<A> {
     _a: PhantomData<A>,
 }
@@ -170,3 +195,29 @@ impl<'a, A: 'a + PartialOrd> BinaryTreesAvl<'a> for AvlTs<A> {
         AvlN { l: tl, r: tr, key }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test() {
+        let trees = AvlTs::new();
+        let mut tree = trees.empty();
+        for i in [
+            8, 3, 10, 17, 0, 13, 6, 1, 11, 5, 4, 7, 18, 14, 15, 9, 2, 19, 16, 12,
+        ] {
+            tree = trees.clone().add_tree(tree, i.into());
+            assert!(tree.balanced());
+            // println!("{} {}", tree.height, tree);
+        }
+        for i in [
+            2, 9, 4, 7, 8, 10, 17, 1, 13, 15, 18, 12, 5, 0, 3, 6, 16, 19, 14, 11,
+        ] {
+            tree = trees.clone().remove(tree, i.into());
+            assert!(tree.balanced());
+            // println!("{} {}", tree.height, tree);
+        }
+        // assert!(false);
+    }
+}