def real_tests_from_dict(self, paths, tests_by_dir):
        """Find all real tests in paths, using results saved in dict."""
        files = []
        for path in paths:
            if self._has_supported_extension_for_all(path):
                files.append(path)
                continue
            path = path + '/' if path[-1] != '/' else path
            for key, value in tests_by_dir.items():
                if key.startswith(path):
                    files.extend(value)
        return files