Use Node::clone() method in order to not alter the original tree when getting using Node::getValue().

Author: drupol

spec/drupol/phptree/Node/MerkleNodeSpec.php

@@ -4,17 +4,16 @@
 
 namespace spec\drupol\phptree\Node;
 
-use drupol\phpmerkle\Hasher\DoubleSha256;
-use drupol\phptree\Node\MerkleNode;
 use drupol\phpmerkle\Hasher\DummyHasher;
+use drupol\phptree\Node\MerkleNode;
 use PhpSpec\ObjectBehavior;
 
 class MerkleNodeSpec extends ObjectBehavior
 {
     public function it_can_get_a_hash()
     {
         $this
-            ->beConstructedWith('root', 2, new DoubleSha256());
+            ->beConstructedWith('root');
 
         $input = [
             null,
@@ -50,7 +49,7 @@ public function it_can_get_a_hash()
         ];
 
         foreach ($input as $word) {
-            $nodes[] = new MerkleNode($word, 2, new DoubleSha256());
+            $nodes[] = new MerkleNode($word);
         }
 
         $this
@@ -77,9 +76,19 @@ public function it_can_get_the_value_of_a_tree_with_four_nodes()
         ];
 
         $this
-            ->add(...$nodes)
+            ->add(...$nodes);
+
+        $this
+            ->count()
+            ->shouldReturn(5);
+
+        $this
             ->getValue()
             ->shouldReturn('abcc');
+
+        $this
+            ->count()
+            ->shouldReturn(5);
     }
 
     public function it_can_get_the_value_of_a_tree_with_three_nodes()
@@ -105,6 +114,33 @@ public function it_can_get_the_value_of_a_tree_with_two_nodes()
             ->shouldReturn('aa');
     }
 
+    public function it_can_handle_null_values()
+    {
+        $nodes = [
+            new MerkleNode(null, 2, new DummyHasher()),
+            new MerkleNode(null, 2, new DummyHasher()),
+            new MerkleNode('a', 2, new DummyHasher()),
+            new MerkleNode('b', 2, new DummyHasher()),
+            new MerkleNode(null, 2, new DummyHasher()),
+            new MerkleNode('c', 2, new DummyHasher()),
+        ];
+
+        $this
+            ->add(...$nodes);
+
+        $this
+            ->count()
+            ->shouldReturn(6);
+
+        $this
+            ->getValue()
+            ->shouldReturn('abcc');
+
+        $this
+            ->count()
+            ->shouldReturn(6);
+    }
+
     public function it_is_initializable()
     {
         $this->shouldHaveType(MerkleNode::class);

src/Node/MerkleNode.php

@@ -43,7 +43,7 @@ public function getValue()
             return parent::getValue();
         }
 
-        return $this->hash();
+        return $this->clone()->hash();
     }
 
     /**