diff --git a/filter/tree_test.c b/filter/tree_test.c
index f1df40c1..de022416 100644
--- a/filter/tree_test.c
+++ b/filter/tree_test.c
@@ -7,42 +7,272 @@
  */
 
 #include "test/birdtest.h"
-#include "test/utils.h"
+#include "test/bt-utils.h"
 
 #include "filter/filter.h"
 
-static void
-show_buffer(buffer *b)
+static struct f_tree *
+new_tree(uint id)
 {
-  byte *p;
-  for (p=b->start; p != b->pos; p++)
-    bt_debug("%c", *p);
-  bt_debug("\n");
+  struct f_tree *tree = f_new_tree();
+  tree->from.type  = tree->to.type  = T_INT;
+  tree->from.val.i = tree->to.val.i = id;
+
+  return tree;
 }
 
-static int
-t_tree(void)
+static void
+show_subtree(struct f_tree *node)
 {
-  bt_bird_init();
+  if (!node)
+    return;
 
-  struct f_tree *a = f_new_tree();
-  struct f_tree *b = f_new_tree();
-  bt_assert(same_tree(a, b));
+  if (node->from.val.i == node->to.val.i)
+    bt_debug("%u ", node->from.val.i);
+  else
+    bt_debug("%u..%u ", node->from.val.i, node->to.val.i);
+  show_subtree(node->left);
+  show_subtree(node->right);
+}
 
-  buffer buffer1;
-  LOG_BUFFER_INIT(buffer1);
-  tree_format(a, &buffer1);
+static void
+show_tree2(struct f_tree *root_node, const char *tree_name)
+{
+  bt_debug("%s: \n", tree_name);
+  bt_debug("[ ");
+  show_subtree(root_node);
+  bt_debug("]\n\n");
+}
 
-  show_buffer(&buffer1);
+#define show_tree(tree) show_tree2(tree, #tree);
+
+static uint
+get_nodes_count_in_full_tree(uint height)
+{
+  return (naive_pow(2, height+1) - 1);
+}
+
+static struct f_tree *
+get_balanced_full_subtree(uint height, uint idx)
+{
+  struct f_tree *node = new_tree(idx);
+  if (height > 0)
+  {
+    uint nodes_in_subtree = get_nodes_count_in_full_tree(--height);
+    node->left  = get_balanced_full_subtree(height, idx - nodes_in_subtree/2 - 1);
+    node->right = get_balanced_full_subtree(height, idx + nodes_in_subtree/2 + 1);
+  }
+  return node;
+}
+
+static struct f_tree *
+get_balanced_full_tree(uint height)
+{
+  return get_balanced_full_subtree(height, get_nodes_count_in_full_tree(height)/2);
+}
+
+static struct f_tree *
+get_degenerated_left_tree(uint nodes_count)
+{
+  struct f_tree **nodes = (struct f_tree **) malloc(nodes_count * sizeof(struct f_tree *));
+
+  int i;
+  for (i = nodes_count-1; i >= 0; i--)
+  {
+    nodes[i] = new_tree(i);
+    if (i != nodes_count-1)
+      nodes[i]->left = nodes[i+1];
+  }
+
+  struct f_tree *root_node = nodes[0];
+  free(nodes);
+
+  return root_node;
+}
+
+static struct f_tree *
+get_random_degenerated_left_tree(uint nodes_count)
+{
+  struct f_tree *tree = get_degenerated_left_tree(nodes_count);
+
+  size_t avaible_indexes_size = nodes_count * sizeof(byte);
+  byte *avaible_indexes = malloc(avaible_indexes_size);
+  bzero(avaible_indexes, avaible_indexes_size);
+
+  struct f_tree *n;
+  for (n = tree; n; n = n->left)
+  {
+    uint selected_idx;
+    do {
+      selected_idx = bt_rand_num() % nodes_count;
+    } while(avaible_indexes[selected_idx] != 0);
+
+    avaible_indexes[selected_idx] = 1;
+    n->from.type  = n->to.type  = T_INT;
+    n->from.val.i = n->to.val.i = selected_idx;
+  }
+
+  free(avaible_indexes);
+  return tree;
+}
+
+static struct f_tree *
+get_balanced_tree_with_ranged_values(uint nodes_count)
+{
+  struct f_tree *tree = get_degenerated_left_tree(nodes_count);
+
+  uint idx = 0;
+  struct f_tree *n;
+  for (n = tree; n; n = n->left)
+  {
+    n->from.type = n->to.type = T_INT;
+    n->from.val.i = idx;
+    idx += (uint)bt_rand_num() / nodes_count;	/* (... / nodes_count) preventing overflow an uint idx */
+    n->to.val.i = idx++;
+  }
+
+  return build_tree(tree);
+}
+
+
+static int
+t_balancing(void)
+{
+  bt_bird_init_with_simple_configuration();
+
+  uint height;
+  for (height = 1; height < 13; height++)
+  {
+    uint nodes_count = get_nodes_count_in_full_tree(height);
+
+    struct f_tree *simple_degenerated_tree = get_degenerated_left_tree(nodes_count);
+    struct f_tree *expected_balanced_tree = get_balanced_full_tree(height);
+    struct f_tree *balanced_tree_from_simple_degenerated = build_tree(simple_degenerated_tree);
+
+    show_tree(simple_degenerated_tree);
+    show_tree(expected_balanced_tree);
+    show_tree(balanced_tree_from_simple_degenerated);
+
+    bt_assert(same_tree(balanced_tree_from_simple_degenerated, expected_balanced_tree));
+  }
 
   return BT_SUCCESS;
 }
+
+static int
+t_balancing_random(void)
+{
+  bt_bird_init_with_simple_configuration();
+
+  uint height;
+  for (height = 1; height < 10; height++)
+  {
+    uint nodes_count = get_nodes_count_in_full_tree(height);
+
+    struct f_tree *expected_balanced_tree = get_balanced_full_tree(height);
+
+    uint i;
+    for(i = 0; i < 10; i++)
+    {
+      struct f_tree *random_degenerated_tree = get_random_degenerated_left_tree(nodes_count);
+      struct f_tree *balanced_tree_from_random_degenerated = build_tree(random_degenerated_tree);
+
+      show_tree(random_degenerated_tree);
+      show_tree(expected_balanced_tree);
+      show_tree(balanced_tree_from_random_degenerated);
+
+      bt_assert(same_tree(balanced_tree_from_random_degenerated, expected_balanced_tree));
+    }
+  }
+
+  return BT_SUCCESS;
+}
+
+static int
+t_find(void)
+{
+  bt_bird_init_with_simple_configuration();
+
+  uint height;
+  for (height = 1; height < 13; height++)
+  {
+    uint nodes_count = get_nodes_count_in_full_tree(height);
+
+    struct f_tree *tree = get_balanced_full_tree(height);
+
+    struct f_val looking_up_value = {
+	.type = T_INT
+    };
+    for(looking_up_value.val.i = 0; looking_up_value.val.i < nodes_count; looking_up_value.val.i++)
+    {
+      struct f_tree *found_tree = find_tree(tree, looking_up_value);
+      bt_assert((val_compare(looking_up_value, found_tree->from) == 0) && (val_compare(looking_up_value, found_tree->to) == 0));
+    }
+  }
+
+  return BT_SUCCESS;
+}
+
+static uint
+get_max_value_in_unbalanced_tree(struct f_tree *node, uint max)
+{
+  if (!node)
+    return max;
+
+  if (node->to.val.i > max)
+    max = node->to.val.i;
+
+  uint max_left  = get_max_value_in_unbalanced_tree(node->left, max);
+  if (max_left > max)
+    max = max_left;
+
+  uint max_right = get_max_value_in_unbalanced_tree(node->right, max);
+  if (max_right > max)
+    max = max_right;
+
+  return max;
+}
+
+static int
+t_find_ranges(void)
+{
+  bt_bird_init_with_simple_configuration();
+
+  uint height;
+  for (height = 1; height < 10; height++)
+  {
+    uint nodes_count = get_nodes_count_in_full_tree(height);
+
+    struct f_tree *tree = get_balanced_tree_with_ranged_values(nodes_count);
+    uint max_value = get_max_value_in_unbalanced_tree(tree, 0);
+    bt_debug("max_value: %u \n", max_value);
+
+    struct f_val looking_up_value = {
+	.type = T_INT
+    };
+    for(looking_up_value.val.i = 0; looking_up_value.val.i <= max_value; looking_up_value.val.i += ((uint)bt_rand_num()/nodes_count))
+    {
+      struct f_tree *found_tree = find_tree(tree, looking_up_value);
+      bt_debug("searching: %u \n", looking_up_value.val.i);
+      bt_assert(
+	  (val_compare(looking_up_value, found_tree->from) == 0) || (val_compare(looking_up_value, found_tree->to) == 0) ||
+	 ((val_compare(looking_up_value, found_tree->from) == 1) && (val_compare(looking_up_value, found_tree->to) == -1))
+      );
+    }
+  }
+
+  return BT_SUCCESS;
+}
+
 int
 main(int argc, char *argv[])
 {
   bt_init(argc, argv);
 
-  bt_test_suite(t_tree, "Tree Test");
+  bt_test_suite(t_balancing, "Balancing strong unbalanced trees");
+  bt_test_suite(t_balancing_random, "Balancing random unbalanced trees");
+  bt_test_suite(t_find, "Finding values in trees");
+  bt_test_suite(t_find_ranges, "Finding values in trees with random ranged values");
 
   return bt_end();
 }