test paginate

Author: brenoroosevelt

composer.json

@@ -45,6 +45,7 @@
             "src/Map.php",
             "src/None.php",
             "src/Only.php",
+            "src/Paginate.php",
             "src/Pipe.php",
             "src/Pull.php",
             "src/Pull.php",

src/Paginate.php

@@ -0,0 +1,25 @@
+<?php
+declare(strict_types=1);
+
+namespace BrenoRoosevelt;
+
+/**
+ * Returns array pagination
+ * If <b>page</b> or <b>per_page</b> is less than 1, this function will return empty array
+ *
+ * @param array $items The array to be paginated
+ * @param int $page The page number (first page is `1`)
+ * @param int $per_page Number of elements per page
+ * @param bool $preserve_keys Preserve keys
+ * @return array
+ */
+function paginate(array $items, int $page, int $per_page, bool $preserve_keys = true): array
+{
+    if ($per_page < 1 || $page < 1) {
+        return [];
+    }
+
+    $offset = max(0, ($page - 1) * $per_page);
+
+    return array_slice($items, $offset, $per_page, $preserve_keys);
+}

src/array_functions.php

@@ -3,25 +3,6 @@
 
 namespace BrenoRoosevelt;
 
-function column(iterable $items, $column): array
-{
-    $result = [];
-    foreach ($items as $element) {
-        if (is_array($element) && array_key_exists($column, $element)) {
-            $result[] = $element[$column];
-        }
-    }
-
-    return $result;
-}
-
-function paginate(array $items, int $page, int $per_page, bool $preserve_keys = true): array
-{
-    $offset = max(0, ($page - 1) * $per_page);
-
-    return array_slice($items, $offset, $per_page, $preserve_keys);
-}
-
 function sum(iterable $items, callable $callback, int $mode = 0)
 {
     $sum = 0;

tests/PaginateTest.php

@@ -0,0 +1,73 @@
+<?php
+declare(strict_types=1);
+
+namespace BrenoRoosevelt\Tests;
+
+use PHPUnit\Framework\TestCase;
+use function BrenoRoosevelt\paginate;
+
+class PaginateTest extends TestCase
+{
+    public function testPaginate()
+    {
+        $elements = range(0, 100);
+        $result = paginate($elements, 1, 5);
+        $this->assertEquals([0, 1, 2, 3, 4], $result);
+    }
+
+    public function testPaginateCase2()
+    {
+        $elements = range(0, 2);
+        $result = paginate($elements, 1, 5);
+        $this->assertEquals([0, 1, 2], $result);
+    }
+
+    public function testPaginateCase3()
+    {
+        $elements = range(0, 8);
+        $result = paginate($elements, 2, 5);
+        $this->assertEquals([5 => 5, 6 => 6, 7 => 7, 8 => 8], $result);
+    }
+
+    public function testPaginateCasePreserveKey()
+    {
+        $elements = range(0, 8);
+        $result = paginate($elements, 2, 5, false);
+        $this->assertEquals([5, 6, 7, 8], $result);
+    }
+
+    public function testPaginateCaseInvalidPage()
+    {
+        $elements = range(0, 8);
+        $result = paginate($elements, 3, 5);
+        $this->assertEquals([], $result);
+    }
+
+    public function testPaginateCaseEmpty()
+    {
+        $elements = [];
+        $result = paginate($elements, 3, 5);
+        $this->assertEquals([], $result);
+    }
+
+    public function testPaginateNegativeOffset()
+    {
+        $elements = range(0, 100);
+        $result = paginate($elements, 3, -2);
+        $this->assertEquals([], $result);
+    }
+
+    public function testPaginateNegativePage()
+    {
+        $elements = range(0, 100);
+        $result = paginate($elements, -1, 5);
+        $this->assertEquals([], $result);
+    }
+
+    public function testPaginatePageZero()
+    {
+        $elements = range(0, 100);
+        $result = paginate($elements, 0, 5);
+        $this->assertEquals([], $result);
+    }
+}