FBMock_Utils::mockClassNameFor PHP Method

    public static function mockClassNameFor($class_name, array $interfaces, array $traits)
    {
        self::assertString($class_name);
        sort($interfaces);
        sort($traits);
        return sprintf('FBMockFramework_%s_%s_%s', self::classNameForMock($class_name), implode('_', (array) str_replace('_', '__', $interfaces)), implode('_', (array) str_replace('_', '__', $traits)));
    }

 public final function createTestDoubleFor($class_name, array $interfaces = array(), array $traits = array(), $method_checker = null)
 {
     FBMock_Utils::assertString($class_name);
     $this->assertAllowed();
     if (!class_exists($class_name) && !interface_exists($class_name)) {
         throw new FBMock_TestDoubleException("Attempting to mock {$class_name} but {$class_name} isn't loaded.");
     }
     $mock_class_name = FBMock_Utils::mockClassNameFor($class_name, $interfaces, $traits);
     $ref_class = new ReflectionClass($class_name);
     if ($ref_class->isInternal() && !FBMock_Utils::isHHVM()) {
         throw new FBMock_TestDoubleException("Trying to mock PHP internal class {$class_name}. Mocking of internal " . "classes is only supported in HHVM.");
     }
     if (!class_exists($mock_class_name, $autoload = false)) {
         $class_generator_class = FBMock_Config::get()->getClassGenerator();
         $class_generator = new $class_generator_class();
         $code = $class_generator->generateCode($ref_class, $mock_class_name, $interfaces, $traits, $method_checker);
         eval($code);
     }
     $mock_object = (new ReflectionClass($mock_class_name))->newInstanceWithoutConstructor();
     return $mock_object;
 }