getSize of the tree and parts of it

src/Tree/Node/NodeTrait.php

@@ -265,6 +265,20 @@ public function getHeight()
         return max($heights) + 1;
     }
 
+    /**
+     * Return the number of nodes in a tree
+     * @return int
+     */
+    public function getSize()
+    {
+        $size = 1;
+        foreach ($this->getChildren() as $child) {
+            $size += $child->getSize();
+        }
+
+        return $size;
+    }
+
     /**
      * {@inheritdoc}
      */

tests/Tree/Node/NodeTest.php

@@ -257,4 +257,32 @@ public function testGetHeight()
         $this->assertEquals(2, $root->getHeight());
         $this->assertEquals(1, $child3->getHeight());
     }
+
+
+    public function testGetSize()
+    {
+        $root = new Node;
+        $root
+            ->addChild($child1 = new Node('child1'))
+            ->addChild($child2 = new Node('child2'))
+            ->addChild($child3 = new Node('child3'))
+        ;
+
+        $child3
+            ->addChild(new Node("a"))
+            ->addChild($child4 = new Node("b"))
+        ;
+
+        $child4->addChild($child5 = new Node("c"));
+        $child5
+            ->addChild(new Node("d"))
+            ->addChild(new Node("f"))
+        ;
+
+        $this->assertEquals(9, $root->getSize());
+        $this->assertEquals(3, $child5->getSize());
+        $this->assertEquals(4, $child4->getSize());
+        $this->assertEquals(6, $child3->getSize());
+        $this->assertEquals(1, $child2->getSize());
+    }
 }