phpunit.assertCount

Code example

<?php declare(strict_types = 1);

use PHPUnit\Framework\TestCase;

class MyTest extends TestCase
{
	public function testItems(): void
	{
		$items = [1, 2, 3];
		$this->assertSame(3, count($items));
	}
}

Why is it reported?

This rule is part of phpstan-phpunit.

Using assertSame() with count() to verify the number of elements in an array or countable object is less readable and produces worse failure messages than the dedicated assertCount() method. PHPUnit's assertCount() is specifically designed for this purpose and provides clearer output when the assertion fails.

This is also reported for assertSame($expected, $variable->count()) on Countable objects.

How to fix it

Replace assertSame() with count() by using assertCount():

 public function testItems(): void
 {
 	$items = [1, 2, 3];
-	$this->assertSame(3, count($items));
+	$this->assertCount(3, $items);
 }

For Countable objects:

-$this->assertSame(3, $collection->count());
+$this->assertCount(3, $collection);