`$expected` and `$actual` are mixed up in failure description when `assertJsonFileEqualsJsonFile()` fails

[sven-81]

Q	A
PHPUnit version	12.0.5
PHP version	8.4.4
Installation Method	Composer

Summary

If failing assertJsonFileEqualsJsonFile expected, actual are mixed up

Current behavior

If assertJsonFileEqualsJsonFile is failing, the output of expected, actual are mixed up.

How to reproduce

File expected.json:
{"key": true}

File actual.json:
{"key": false}

<?php
declare(strict_types=1);

use PHPUnit\Framework\TestCase;
class JsonTest extends TestCase
{
    public function testAssertJson(): void
    {
        $expected =__DIR__ . '/expected.json';
        $actual =__DIR__ . '/actual.json';

        $this->assertJsonFileEqualsJsonFile($expected, $actual);
    }
}

PHP 8.4.4 (cli) (built: Feb 25 2025 02:19:56) (NTS)
Copyright (c) The PHP Group
Built by https://github.com/docker-library/php
Zend Engine v4.4.4, Copyright (c) Zend Technologies
    with Xdebug v3.4.1, Copyright (c) 2002-2025, by Derick Rethans

PHPUnit 12.0.5 by Sebastian Bergmann and contributors.
Runtime:       PHP 8.4.4

.F......                                                            8 / 8 (100%)

Time: 00:00.024, Memory: 12.00 MB

There was 1 failure:

1) placementDetermination\book\PageTest::testName
Failed asserting that '{\n
  "key": true\n
}' matches JSON string "{
  "key": false
}".
--- Expected
+++ Actual
@@ @@
 {
-    "key": false
+    "key": true
 }

Expected behavior

--- Expected
+++ Actual
@@ @@
 {
-    "key": true
+    "key": false
 }