node wrapper and node builder test

tests/iterators.phpt

@@ -44,6 +44,8 @@ Environment::setup();
         $to->setParent($from);
     };
 
+    // Tree from here:
+    // https://en.wikipedia.org/wiki/Tree_traversal
     $root = $f;
     $edge($f, $b);
     $edge($b, $a);

tests/nodes.phpt

@@ -0,0 +1,90 @@
+<?php
+
+declare(strict_types=1);
+
+use Dakujem\Oliva\Node;
+use Dakujem\Oliva\Simple\NodeBuilder;
+use Dakujem\Oliva\Simple\TreeWrapper;
+use Tester\Assert;
+use Tester\Environment;
+
+require_once __DIR__ . '/../vendor/autoload.php';
+Environment::setup();
+
+(function () {
+    $builder = new NodeBuilder(fn(mixed $data) => new Node($data));
+
+    // Tree from here:
+    // https://en.wikipedia.org/wiki/Tree_traversal
+    $root = $builder->node('F', [
+        $builder->node('B', [
+            $builder->node('A'),
+            $builder->node('D', [
+                $builder->node('C'),
+                $builder->node('E'),
+            ]),
+        ]),
+        $builder->node('G', [
+            $builder->node('I', [
+                $builder->node('H'),
+            ]),
+        ]),
+    ]);
+
+    // pre-order
+    $str = [];
+    foreach ($root as $node) {
+        $str[] = $node->data();
+    }
+    Assert::same('F,B,A,D,C,E,G,I,H', implode(',', $str));
+
+
+    // Tree from here:
+    // https://en.wikipedia.org/wiki/Tree_traversal
+    $data = [
+        'data' => 'F',
+        'children' => [
+            [
+                'data' => 'B',
+                'children' => [
+                    [
+                        'data' => 'A',
+                    ],
+                    [
+                        'data' => 'D',
+                        'children' => [
+                            [
+                                'data' => 'C',
+                            ],
+                            [
+                                'data' => 'E',
+                            ],
+                        ],
+                    ],
+                ],
+            ],
+            [
+                'data' => 'G',
+                'children' => [
+                    [
+                        'data' => 'I',
+                        'children' => [
+                            [
+                                'data' => 'H',
+                            ],
+                        ],
+                    ],
+                ],
+            ],
+        ],
+    ];
+    $wrapper = new TreeWrapper(fn(array $raw) => new Node($raw['data']), fn(array $raw) => $raw['children'] ?? null);
+    $root = $wrapper->wrap($data);
+
+    // pre-order
+    $str = [];
+    foreach ($root as $node) {
+        $str[] = $node->data();
+    }
+    Assert::same('F,B,A,D,C,E,G,I,H', implode(',', $str));
+})();