How to Upgrade to PHPUnit 10 in Diffs

What has changed regarding the dependencies?

• PHPUnit 10 now requires PHP 8.1+
• and it requires Sebastian/diff 5.0 instead of 4.0

The first is a hard requirement, so if you're stuck on PHP 8.0, do not upgrade.

The second one can be vendor locked by other packages. If the Sebastian/diff is a blocker for you, use the composer alias to allow it:

 {
     "require": {
-        "sebastian/diff": "^4.0"
+        "sebastian/diff": "5.0 as 4.0.4"
     }
 }

Update the Differ class

Do you use the sebastian/diff in your code? The Differ class now requires an explicit dependency via a constructor. So add it:

 use SebastianBergmann\Diff\Differ;
 use SebastianBergmann\Diff\Output\StrictUnifiedDiffOutputBuilder;

+$unifiedDiffOutputBuilder = new UnifiedDiffOutputBuilder();
-$differ = new Differ()
+$differ = new Differ($unifiedDiffOutputBuilder);

Update .gitignore paths

New PHPUnit 10 uses the whole directory for caching instead of a single file:

 # .gitignore
-.phpunit.result.cache
+/.phpunit.cache

And the Rest?

• data providers must be static methods now
• the @annotations are flipped to #[attributes]
• the abstract "test" must have TestCase suffix

 use PHPUnit\Framework\TestCase;
+use PHPUnit\Framework\Attributes\DataProvider;

 final class SomeTest extends TestCase
 {
-    /**
-     * @dataProvider provideData()
-     */
+    #[DataProvider('provideData')]
     public function test(int $value)
     {
     }


-    public function provideData()
+    public static function provideData()
     {
        yield [10_0];
     }
}

Note: Do your data providers contain dynamic method calls? You'll need to refactor them to static ones first:

 public static function provideData()
 {
-    yield $this->loadDirectory(__DIR__ . '/Fixtures');
+    yield self::loadDirectory(__DIR__ . '/Fixtures');
 }

The abstract test now has to have *TestCase suffix:

 use PHPUnit\Framework\TestCase;

-abstract AbstractTypeTest extends TestCase
+abstract AbstractTypeTestCase extends TestCase
 {
 }

To handle these, add PHPUnit 10 upgrade set to the rector.php config:

use Rector\Config\RectorConfig;
use Rector\PHPUnit\Set\PHPUnitSetList;

return static function (RectorConfig $rectorConfig): void {
    $rectorConfig->sets([
        PHPUnitSetList::PHPUNIT_100,
    ]);
};

Then run Rector on tests to upgrade:

vendor/bin/rector tests

That's it! We made an upgrade of Rector tests based on this tutorial.

Enjoy your new PHPUnit 10 tests today!

Happy coding!