python - Mock an entire package with pytest and pytest-mock -

September 15, 2012

i have class uses package tmdbsimple:

movie.py

import tmdbsimple tmdb  tmdb.api_key = '12345'  class movie():     def __init__(self, tmdb_id):         movie = tmdb.movies(tmdb_id)         response = movie.info()          self.tmdb_id = tmdb_id         self.title = movie.title         self.vote_average = movie.vote_average         self.watched = false *snip*

this , until want test without relying on actual connection tmdb:

test_movie.py

import pytest  import movie fake_tmdbsimple import faketmdbsimple  @pytest.fixture def testmovie(mocker):     mocker.patch.dict('sys.modules', {'tmdbsimple': faketmdbsimple()})     return movie.movie('1')  def test_creation_of_movie(testmovie):     assert isinstance(testmovie, movie.movie)  def test_properties_of_movie(testmovie):     assert testmovie.tmdb_id == 1     assert testmovie.title == 'example movie'     assert testmovie.vote_average == 10     assert testmovie.watched == false

fake_tmdbsimple.py

class faketmdbsimple():     def __init__(self):         pass      class movies():         _example_movie_data = {             1: {                 'title': 'example movie',                 'vote_average': 10.0             }         }          def __init__(self, tmdb_id):             self.tmdb_id = tmdb_id          def info(self):             self.title = self._example_movie_data[self.tmdb_id]['title']             self.vote_average = self._example_movie_data[self.tmdb_id]['vote_average']      class find():         def __init__(self, identifier):             pass          def info(self, external_source):             return {                 'movie_results': [                     {'id': 1}                 ]             }      class search():         def __init__(self):             pass          def movie(self, query):             return {                 'results': [                     {                         'id': 1                     }                 ]             }

when test runs, error:

*snip* self = <tmdbsimple.movies.movies object @ 0x110779cf8>      def __init__(self): >       . import api_version e       importerror: cannot import name 'api_version'

the test still trying import real tmdbsimple! testmovie object still receives instance of tmdbsimple.movies.movies instead of fake_tmdbsimple.movies when calling tmdb.movies(). relatively sure result of "not mocking object used, coming from." however, in case, using pytest , pytest-mock, not know how make mock happen needs to.

am going right way? if so, need mock entire tmdbsimple package? if not, correct way test movie() class without accessing tmdb?

i had working implementation of before, so:

test_movie.py:

import pytest  pycoin import movie  @pytest.fixture def testmovie(fake_tmdbsimple):     return movie.movie('1')  @pytest.fixture def fake_tmdbsimple(monkeypatch):     monkeypatch.setattr('tmdbsimple.movies', faketmdbsimplemovies)     monkeypatch.setattr('tmdbsimple.find', faketmdbsimplefind)     monkeypatch.setattr('tmdbsimple.search', faketmdbsimplesearch)  class faketmdbsimplemovies():     _example_movie_data = {         1: {             'title': 'example movie',             'vote_average': 10.0         }     }      def __init__(self, tmdb_id):         self.tmdb_id = tmdb_id      def info(self):         self.title = self._example_movie_data[self.tmdb_id]['title']         self.vote_average = self._example_movie_data[self.tmdb_id]['vote_average']  class faketmdbsimplefind():     def __init__(self, identifier):         pass      def info(self, external_source):         return {             'movie_results': [                 {'id': 1}             ]         }  class faketmdbsimplesearch():     def __init__(self):         pass      def movie(self, query):         return {             'results': [                 {                     'id': 1                 }             ]         }  def test_creation_of_movie(testmovie):     assert isinstance(testmovie, movie.movie)  def test_properties_of_movie(testmovie):     assert testmovie.tmdb_id == 1     assert testmovie.title == 'example movie'     assert testmovie.vote_average == 10     assert testmovie.watched == false

this had advantage of not requiring pytest-mock (and advantage of working...), seemed inelegant patch each of movies, find, , search individually. require re-implementation of fake classes if wanted test other modules fake version of tmdbsimple. annoys completionist in me tried mock out entire package can't figure out how.