feat: calling slice() on a LazyMatchingReadableCollection` now shou…

…ld not trigger initialization of the underlying collection. (#12)

* feat: calling `slice()` on a LazyMatchingReadableCollection` now should not trigger initialization of the underlying collection.

* remove order to pass test

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## 2.3.0
 
+* feat: calling `slice()` on a `LazyMatchingReadableCollection` now should not
+  trigger initialization of the underlying collection.
 * test: improve `LazyMatchingTest`
 
 ## 2.2.0

src/LazyMatching/LazyMatchingReadableCollection.php

@@ -79,4 +79,17 @@ public function matching(Criteria $criteria): ReadableCollection&Selectable
 
         return $clone;
     }
+
+    public function slice(int $offset, ?int $length = null): array
+    {
+        if ($this->criteria === null) {
+            return parent::slice($offset, $length);
+        }
+
+        $criteria = (clone $this->criteria)
+            ->setFirstResult($offset)
+            ->setMaxResults($length);
+
+        return $this->matching($criteria)->toArray();
+    }
 }

src/LazyMatching/LazyMatchingReadableCollectionFromSelectable.php

@@ -63,4 +63,13 @@ public function matching(Criteria $criteria): ReadableCollection&Selectable
 
         return $clone;
     }
+
+    public function slice(int $offset, ?int $length = null): array
+    {
+        $criteria = (clone $this->criteria)
+            ->setFirstResult($offset)
+            ->setMaxResults($length);
+
+        return $this->matching($criteria)->toArray();
+    }
 }

tests/LazyMatchingTest.php

@@ -15,12 +15,14 @@
 
 use Doctrine\Common\Collections\ArrayCollection;
 use Doctrine\Common\Collections\Criteria;
+use Doctrine\Common\Collections\Order;
 use PHPUnit\Framework\TestCase;
 use Rekalogika\Collections\Decorator\LazyMatching\LazyMatchingCollection;
 use Rekalogika\Collections\Decorator\LazyMatching\LazyMatchingReadableCollection;
 use Rekalogika\Collections\Decorator\Tests\Model\Book;
 use Rekalogika\Collections\Decorator\Tests\Model\BookShelf;
 use Rekalogika\Collections\Decorator\Tests\Model\SelectableInterceptor;
+use Rekalogika\Collections\Decorator\Tests\Model\SliceInterceptor;
 
 class LazyMatchingTest extends TestCase
 {
@@ -122,4 +124,37 @@ public function testCriteria(): void
             $result->toArray()
         );
     }
+
+    public function testSlice(): void
+    {
+        $bookshelf = new BookShelf();
+        $bookshelf->set('a', new Book('A', 100, 'Author A'));
+        $bookshelf->set('b', new Book('B', 200, 'Author B'));
+        $bookshelf->set('c', new Book('C', 300, 'Author C'));
+        $bookshelf->set('d', new Book('D', 50, 'Author C'));
+        $bookshelf->set('e', new Book('E', 20, 'Author C'));
+        $bookshelf->set('f', new Book('F', 500, 'Author C'));
+
+        $bookshelf = new SliceInterceptor($bookshelf);
+        $realBookShelf = $bookshelf;
+
+        $bookshelf = new LazyMatchingCollection($bookshelf);
+        $criteria = Criteria::create()
+            ->where(Criteria::expr()->gt('numOfPages', 60));
+
+        $filtered = $bookshelf->matching($criteria);
+        $count = $filtered->count();
+        $this->assertSame(4, $count);
+
+        $sliced = $filtered->slice(1, 2);
+        $this->assertEquals(
+            [
+                'b' => new Book('B', 200, 'Author B'),
+                'c' => new Book('C', 300, 'Author C'),
+            ],
+            $sliced
+        );
+
+        $this->assertEquals(0, $realBookShelf->getSliceCount());
+    }
 }

tests/Model/SliceInterceptor.php

@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of rekalogika/doctrine-collections-decorator package.
+ *
+ * (c) Priyadi Iman Nurcahyo <https://rekalogika.dev>
+ *
+ * For the full copyright and license information, please view the LICENSE file
+ * that was distributed with this source code.
+ */
+
+namespace Rekalogika\Collections\Decorator\Tests\Model;
+
+use Rekalogika\Collections\Decorator\Decorator\SelectableCollectionDecorator;
+
+/**
+ * @extends SelectableCollectionDecorator<int|string,Book>
+ */
+class SliceInterceptor extends SelectableCollectionDecorator
+{
+    private int $sliceCount = 0;
+
+    public function count(): int
+    {
+        $this->sliceCount++;
+        return $this->getWrapped()->count();
+    }
+
+    public function getSliceCount(): int
+    {
+        return $this->sliceCount;
+    }
+}