Inital commit after splitting from project

tests/FlattenTest.php

@@ -0,0 +1,65 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tez\Utils\Tests\Arr;
+
+use PHPUnit\Framework\TestCase;
+use Tez\Utils\Arr\Flatten;
+
+final class FlattenTest extends TestCase
+{
+    public function testFlattensFullyByDefault(): void
+    {
+        $result = Flatten::flatten([1, [2, 3], [4, [5, 6]]]);
+
+        self::assertSame([1, 2, 3, 4, 5, 6], $result);
+    }
+
+    public function testDepthOne(): void
+    {
+        $result = Flatten::flatten([1, [2, 3], [4, [5, 6]]], depth: 1);
+
+        self::assertSame([1, 2, 3, 4, [5, 6]], $result);
+    }
+
+    public function testDepthTwo(): void
+    {
+        $result = Flatten::flatten([1, [2, [3, [4]]]], depth: 2);
+
+        self::assertSame([1, 2, 3, [4]], $result);
+    }
+
+    public function testAlreadyFlatArrayIsUnchanged(): void
+    {
+        $result = Flatten::flatten([1, 2, 3]);
+
+        self::assertSame([1, 2, 3], $result);
+    }
+
+    public function testEmptyArrayReturnsEmpty(): void
+    {
+        self::assertSame([], Flatten::flatten([]));
+    }
+
+    public function testAssociativeKeysAreDiscarded(): void
+    {
+        $result = Flatten::flatten([['a' => 1, 'b' => 2], ['c' => 3]]);
+
+        self::assertSame([1, 2, 3], $result);
+    }
+
+    public function testDepthZeroReturnsOriginalValues(): void
+    {
+        $result = Flatten::flatten([[1, 2], [3, 4]], depth: 0);
+
+        self::assertSame([[1, 2], [3, 4]], $result);
+    }
+
+    public function testMixedNestingDepths(): void
+    {
+        $result = Flatten::flatten([1, [2, [3]], 4, [[5]]]);
+
+        self::assertSame([1, 2, 3, 4, 5], $result);
+    }
+}