N98\Util\ArrayFunctions::mergeArrays PHP Method

    public static function mergeArrays(array $a, array $b)
    {
        foreach ($b as $key => $value) {
            if (array_key_exists($key, $a)) {
                if (is_int($key)) {
                    $a[] = $value;
                } elseif (is_array($value) && is_array($a[$key])) {
                    $a[$key] = self::mergeArrays($a[$key], $value);
                } else {
                    $a[$key] = $value;
                }
            } else {
                $a[$key] = $value;
            }
        }
        return $a;
    }

 public function testExecute()
 {
     /**
      * Check autoloading
      */
     /* @var $application Application */
     $application = (require __DIR__ . '/../../../src/bootstrap.php');
     $application->setMagentoRootFolder($this->getTestMagentoRoot());
     $this->assertInstanceOf('\\N98\\Magento\\Application', $application);
     $loader = $application->getAutoloader();
     $this->assertInstanceOf('\\Composer\\Autoload\\ClassLoader', $loader);
     /**
      * Check version
      */
     $this->assertEquals(Application::APP_VERSION, trim(file_get_contents(__DIR__ . '/../../../version.txt')));
     /* @var $loader \Composer\Autoload\ClassLoader */
     $prefixes = $loader->getPrefixes();
     $this->assertArrayHasKey('N98', $prefixes);
     $distConfigArray = Yaml::parse(file_get_contents(__DIR__ . '/../../../config.yaml'));
     $configArray = array('autoloaders' => array('N98MagerunTest' => __DIR__ . '/_ApplicationTestSrc'), 'commands' => array('customCommands' => array(0 => 'N98MagerunTest\\TestDummyCommand'), 'aliases' => array(array('ssl' => 'sys:store:list'))), 'init' => array('options' => array('config_model' => 'N98MagerunTest\\AlternativeConfigModel')));
     $application->setAutoExit(false);
     $application->init(ArrayFunctions::mergeArrays($distConfigArray, $configArray));
     $application->run(new StringInput('list'), new NullOutput());
     // Check if autoloaders, commands and aliases are registered
     $prefixes = $loader->getPrefixes();
     $this->assertArrayHasKey('N98MagerunTest', $prefixes);
     $testDummyCommand = $application->find('n98mageruntest:test:dummy');
     $this->assertInstanceOf('\\N98MagerunTest\\TestDummyCommand', $testDummyCommand);
     $commandTester = new CommandTester($testDummyCommand);
     $commandTester->execute(array('command' => $testDummyCommand->getName()));
     $this->assertContains('dummy', $commandTester->getDisplay());
     $this->assertTrue($application->getDefinition()->hasOption('root-dir'));
     // check alias
     $this->assertInstanceOf('\\N98\\Magento\\Command\\System\\Store\\ListCommand', $application->find('ssl'));
 }