feat(lsm): binary tree iterators

lsm/test/bt/bt.c

@@ -104,6 +104,33 @@ void test_remove_multiple() {
   lsm_bt_free(bt);
 }
 
+void test_iter() {
+  char chars[] = "falcoep";
+  size_t char_count = sizeof(chars) / sizeof(char) - 1;
+
+  char sorted_chars[] = "aceflop";
+
+  BT_INIT();
+
+  for (size_t i = 0; i < char_count; i++) {
+    TEST_CHECK(lsm_bt_insert(bt, chars[i], (void *)(i + 1)) == lsm_error_ok);
+  }
+
+  lsm_bt_iterator iter;
+  lsm_bt_iter(&iter, bt);
+
+  char key;
+  const void *data;
+  size_t i = 0;
+
+  while (lsm_bt_iter_next(&data, &key, &iter)) {
+    TEST_CHECK_(key == sorted_chars[i], "%c == %c", key, sorted_chars[i]);
+    i++;
+  }
+
+  TEST_CHECK(i == char_count);
+}
+
 TEST_LIST = {
   { "bt init", test_init },
   { "bt insert first", test_insert_first },
@@ -111,5 +138,6 @@ TEST_LIST = {
   { "bt insert multiple", test_insert_multiple },
   { "bt remove root", test_remove_root },
   { "bt remove multiple", test_remove_multiple },
+  { "bt iter", test_iter },
   { NULL, NULL }
 };