settings created by ragnarok22 - https://repl.it/KaLA/68

es.lng

# esto es un comentario
setting:configuración
language:idioma # esto es otro comentario

language.py

import sys
import warnings


class LanguageNotFoundError(FileNotFoundError):
	def __init__(self, message):
		super(LanguageNotFoundError, self).__init__()
		self.message = message


class Language(object):
	def __init__(self, lang='en'):
		self.lang = lang

	def get_lang(self):
		return self.lang

	def set_lang(self, lang):
		self.lang = lang


def read_lang_file(lang):
	'''
	retorna un str que solo contiene los valores del idioma y la traducción
	'''
	file = lang + '.lng'
	string = ""
	try:
		with open(file, 'r') as f:
			for w in f.readlines():
				temp = w.split('#')
				string += temp[0]
		return string
	except FileNotFoundError:
		raise LanguageNotFoundError('The language File "{0}" was not found on folder language'.format(file))
	except:
		print('Error inesperado', sys.exc_info()[0])

def words_dic(str_file):
	"""
	@params: str_file es un str, es el contenido del fichero
	@return: un diccionario con las palabras como llave y su traduccion como valor
	"""
	result = {}
	current = str_file.split('\n')
	for i in current:
		temp = i.split(':')
		result[temp[0]] = temp[1]
	return result
	
def gettext(text, parent):
	try:
		lang_file = read_lang_file(parent.lang)
	except LanguageNotFoundError as e:
		warnings.warn("Language not found. {0}".format(e.message), UserWarning)
		return text # el idioma especificado no se encontro y se retorna el mismo texto
	words = words_dic(lang_file)
	result = words.get(text, None)
	if result:
		return result # si la palabra se encuentra en el fichero se retorna
	else:
		return text # sino se retorna el mismo texto

main.py

import unittest
import language


class TestLanguageClass(unittest.TestCase):
	def setUp(self):
		class Window(language.Language):
			def __init__(self):
				super(Window, self).__init__()
				self.lang = 'es'
				self.btn = language.gettext('setting', self)
		self.window = Window()
	
	def test_translate(self):
		self.assertEqual(self.window.btn, 'configuración')

		
class TestLanguageClassInherit(unittest.TestCase):
	def setUp(self):
		class Window(language.Language):
			def __init__(self):
				super(Window, self).__init__()
				self.btn = language.gettext('setting', self)
		self.window = Window()
	
	def test_translate(self):
		self.assertEqual(self.window.btn, 'setting')
		
		
if __name__ == '__main__':
	unittest.main()