Add related tests.

Author: drupol

spec/drupol/phptree/Node/TrieNodeSpec.php

@@ -0,0 +1,42 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace spec\drupol\phptree\Node;
+
+use drupol\phptree\Node\KeyValueNode;
+use drupol\phptree\Node\TrieNode;
+use PhpSpec\ObjectBehavior;
+
+class TrieNodeSpec extends ObjectBehavior
+{
+    public function it_is_initializable()
+    {
+        $this->shouldHaveType(TrieNode::class);
+    }
+
+    public function it_can_add_node()
+    {
+        $this->beConstructedWith('root', 'root');
+
+        $nodes = [
+            'ab',
+            'abc',
+            'abcd',
+            'abcde',
+            'cb',
+            'cba',
+            'dcba',
+            'edcba',
+        ];
+
+        foreach ($nodes as $key => $value) {
+            $nodes[$key] = new KeyValueNode($key, $value);
+        }
+
+        $this
+            ->add(...$nodes)
+            ->count()
+            ->shouldReturn(25);
+    }
+}