public function main(string $pathToTestsDirectory): array
    {
        if (!is_dir($pathToTestsDirectory)) {
            throw new \InvalidArgumentException(
                '$pathToTestsDirectory "' . $pathToTestsDirectory . '" does not exist"'
            );
        }
        $this->largePath  = $pathToTestsDirectory . '/Large';
        $this->mediumPath = $pathToTestsDirectory . '/Medium';
        $this->smallPath  = $pathToTestsDirectory . '/Small';
        $this->checkLarge();
        $this->checkMedium();
        $this->checkSmall();

        return $this->errors;
    }