I have this very simple code which I am failing to see how to reach a coverage target of 100%.

final class StringValidator
{
    public function matches(
        string $pattern,
        string $string
    ): bool {
        $result = @preg_match($pattern, $string);

        if (false === $result) {
            throw new InvalidRegexPatternException();
        }

        return (bool) $result;
    }
}

The test file contains :

/**
 * @covers StringValidator
 */
final class StringValidatorTest extends TestCase
{
    private StringValidator $validator;

    protected function setUp(): void
    {
        $this->validator = new StringValidator();
    }

    public function testMatchThrowsOnInvalidRegex(): void
    {
        $this->expectException(InvalidRegexPatternException::class);

        $this->validator->matches('/', 'string');
    }

    public function testMatchReturns0WhenNoMatchIsFound(): void
    {
        $result = $this->validator->matches('/xyz/', 'abc');

        $this->assertFalse($result);
    }

    public function testMatchReturns1WhenMatchIsFound(): void
    {
        $result = $this->validator->matches('/abc/', 'abc');

        $this->assertTrue($result);
    }
}

The coverage reports indicates this :

StringValidator
  Methods:   0.00% ( 0/ 1)   Paths:  50.00% (  2/  4)   Branches:  83.33% (  5/  6)   Lines: 100.00% (  4/  4)

I struggle to understand which methods, paths and branches I am missing. There may be tools (or ways to use and understand the tools I have) that I am unaware of, so guidance about how to interpret this result will be appreciated.

I run PHP Unit with :

php -d xdebug.mode=debug vendor/bin/phpunit --configuration config/phpunit.xml --coverage-text

I do delete phpunit's cache quite often to be sure it's not a cache issue.

If the configuration can be relevant, here's my phpunit.xml :

    
        
    

    
        
            ../sources
        
        
            
            ../sources/**/**/**/Entity
            ../sources/**/**/Entity

            
            ../sources/**/**/**/ValueObject
            ../sources/**/**/ValueObject

            
            ../sources/**/**/**/Enum
            ../sources/**/**/Enum

            
            ../sources/**/**/**/Repository
            ../sources/**/**/Repository

            
            ../sources/**/**/**/Exception
            ../sources/**/**/Exception

            
            ../sources/**/**/**/Event
            ../sources/**/**/Event

            
            ../sources/**/**/**/Command
            ../sources/**/**/Command

            
            ../sources/**/**/**/Query
            ../sources/**/**/Query

            
            ../sources/**/**/**/DTO
            ../sources/**/**/DTO

            
            ../sources/**/**/Test
            ../sources/**/Test

            
            ../sources/**/**/Config
            ../sources/**/Config
        
        
            
            
            
            
            
            
            
        
    

    
        
        
        
        
        
        
    

    
        
            ../tests/Unit
        

        
            ../sources/**/Test
        

        
            ../sources/SubDomains/**/Test
        

    

I use PHP Unit 9.6.34, and php --version outputs :

PHP 8.4.12 (cli) (built: Sep  8 2025 21:18:18) (NTS)
Copyright (c) The PHP Group
Built by https://github.com/docker-library/php
Zend Engine v4.4.12, Copyright (c) Zend Technologies
    with Zend OPcache v8.4.12, Copyright (c), by Zend Technologies
    with Xdebug v3.5.1, Copyright (c) 2002-2026, by Derick Rethans