diff --git a/test/merkle_tree_test.exs b/test/merkle_tree_test.exs
index 7760606..7da89c2 100644
--- a/test/merkle_tree_test.exs
+++ b/test/merkle_tree_test.exs
@@ -31,4 +31,30 @@ defmodule MerkleTreeTest do
     assert MerkleTree.new(blocks).root ==
              MerkleTree.new(blocks |> Enum.map(&MerkleTree.Crypto.sha256/1), hash_leaf: false).root
   end
+
+  test "default hash function sha256" do
+    blocks = ['a', 'a', 'a', 'a']
+    assert MerkleTree.new(blocks, &MerkleTree.Crypto.sha256/1) == MerkleTree.new(blocks)
+  end
+
+  test "merkle tree node" do
+    hash = &MerkleTree.Crypto.sha256/1
+
+    assert MerkleTree.build(['a', 'b'], &MerkleTree.Crypto.sha256/1) == %MerkleTree.Node{
+             children: [
+               %MerkleTree.Node{
+                 children: [],
+                 height: 0,
+                 value: hash.('a')
+               },
+               %MerkleTree.Node{
+                 children: [],
+                 height: 0,
+                 value: hash.('b')
+               }
+             ],
+             height: 1,
+             value: hash.(hash.('a') <> hash.('b'))
+           }
+  end
 end