Improve tests to validate the correct contents of extracted files

Currently the tests primarily check that the correct number of files are returned from extraction commands. However, as the issue identified in #102 shows this can be insufficient in cases where the underlying library may not be threadsafe (for example). In such cases the tests can still succeed, finding the correct number of files, but their contents may be incomplete. We should develop additional tests that verify for each file type we support that the contents + sizes of each file are correct. Perhaps the easiest method would be with a hash of the contents of the extracted stream.

Comienza localizando las pruebas existentes para los comandos de extracción y revisa el issue #102 para conocer el escenario de fallo. Amplía la cobertura para cada tipo de archivo compatible, de modo que las pruebas verifiquen el contenido y los tamaños de los archivos extraídos, potencialmente calculando el hash de cada stream extraído. Se considera completado cuando las pruebas detectan contenido incompleto incluso si se devuelve el número de archivos esperado.