Cutting off the Internet: Testing Applications That Use Requests

requests is a very popular library for making HTTP requests in Python. Even though so many people use it, there's no thorough and exhaustive way to test applications that take advantage of it.

These slides are best read while listening to the presentation given at PyTennessee on 7 February 2015

Transcript

1. Testing applications that use requests Cutting off the Internet
3. Object Placeholder 3 www.rackspace.com
4. 4 • github3.py • twine • urllib3 • sqlobject • betamax @sigmavirus24 (Ian the RFC Reader) www.rackspace.com • requests • Flake8 • chardet • requests-toolbelt • uritemplate.py
5. Object Placeholder 5 www.rackspace.com
6. Why listen to me? 6 www.rackspace.com
7. Why listen to me? 7 www.rackspace.com
8. First, some review 8 www.rackspace.com
9. What is a unit of code? 9 www.rackspace.com
10. What is a unit test? 10 www.rackspace.com
11. What are collaborators? 11 www.rackspace.com
12. Why are they important? 12 www.rackspace.com
13. class Foo(object): def fiz(self, *args): pass A Collaborators Example… 13 www.rackspace.com
14. class Bar(object): def __init__(self): self.foo = Foo() def baz(self, *args): a = self.foo.fiz() # do stuff with a A Collaborators Example… 14 www.rackspace.com
15. What are integration tests? 15 www.rackspace.com
16. Reminder: Tests should be fast 16 www.rackspace.com
17. Time for some code 17 www.rackspace.com
18. def get_resource(session, resource, params=None, headers=None): What We’re Testing 18 www.rackspace.com
19. url = url_from(resource) kw = {‘headers’: headers, ‘params’: params} resp = session.get(url, **kw) if resp.ok: return resp resp.raise_for_status() What We’re Testing 19 www.rackspace.com
20. Why should we test this? 20 www.rackspace.com
21. Why should we test this? 21 www.rackspace.com
22. Why should we test this? 22 www.rackspace.com
23. Approach the first 23 www.rackspace.com
24. • responses • httpretty • requests-mock Available Libraries 24 www.rackspace.com
25. • responses • httpretty • requests-mock Available Libraries 25 www.rackspace.com
26. import my_module import responses import requests Our First Test 26 www.rackspace.com
27. @responses.activate def test_get_resource(): Our First Test 27 www.rackspace.com
28. responses.add( responses.GET, ‘https://api.github.com/users’, body=('[{"id": 1, "url": “https://' 'api.github.com/user/foo”}]'), status=200, content_type=‘application/json') Our First Test 28 www.rackspace.com
29. session = requests.Session() resp = my_module.get_resource( session, ‘/users’) assert resp.json() is not None Our First Test 29 www.rackspace.com
30. $ py.test responses_ex.py responses_ex.py . Running Our First Test 30 www.rackspace.com
31. session = requests.Session() resp = my_module.get_resource( session, ‘/user’) assert resp.json() is not None Making Our Test Fail 31 www.rackspace.com
32. $ py.test responses_ex.py responses_ex.py F Making Our Test Fail 32 www.rackspace.com
33. $ py.test responses_ex.py responses_ex.py F ... ConnectionError: Connection refused: https://api.github.com/ user Making Our Test Fail 33 www.rackspace.com
34. responses.calls responses.calls[0].request Inspecting the Requests Made 34 www.rackspace.com
35. Why is this good? 35 www.rackspace.com
36. Why is this insufficient? 36 www.rackspace.com
37. { "id": 3710711, "name": "github3.py", "full_name": "sigmavirus24/github3.py", "owner": { "login": "sigmavirus24", "id": 240830, "avatar_url": "https://avatars.githubusercontent.com/u/240830?v=3", "gravatar_id": "", "url": "https://api.github.com/users/sigmavirus24", "html_url": "https://github.com/sigmavirus24", "followers_url": "https://api.github.com/users/sigmavirus24/followers", "following_url": "https://api.github.com/users/sigmavirus24/following{/other_user}", "gists_url": "https://api.github.com/users/sigmavirus24/gists{/ gist_id}", "starred_url": "https://api.github.com/users/sigmavirus24/starred{/owner}{/repo}", "subscriptions_url": "https://api.github.com/ users/sigmavirus24/subscriptions", "organizations_url": "https://api.github.com/users/sigmavirus24/orgs", "repos_url": "https:// api.github.com/users/sigmavirus24/repos", "events_url": "https://api.github.com/users/sigmavirus24/events{/privacy}", "received_events_url": "https://api.github.com/users/sigmavirus24/received_events", "type": "User", "site_admin": false }, "private": false, "html_url": "https://github.com/sigmavirus24/github3.py", "description": "Python library for interfacing with the GitHub APIv3", "fork": false, "url": "https://api.github.com/repos/sigmavirus24/github3.py", "forks_url": "https://api.github.com/repos/sigmavirus24/ github3.py/forks", "keys_url": "https://api.github.com/repos/sigmavirus24/github3.py/keys{/key_id}", "collaborators_url": "https:// api.github.com/repos/sigmavirus24/github3.py/collaborators{/collaborator}", "teams_url": "https://api.github.com/repos/sigmavirus24/ github3.py/teams", "hooks_url": "https://api.github.com/repos/sigmavirus24/github3.py/hooks", "issue_events_url": "https://api.github.com/ repos/sigmavirus24/github3.py/issues/events{/number}", "events_url": "https://api.github.com/repos/sigmavirus24/github3.py/events", "assignees_url": "https://api.github.com/repos/sigmavirus24/github3.py/assignees{/user}", "branches_url": "https://api.github.com/repos/ sigmavirus24/github3.py/branches{/branch}", "tags_url": "https://api.github.com/repos/sigmavirus24/github3.py/tags", "blobs_url": "https:// api.github.com/repos/sigmavirus24/github3.py/git/blobs{/sha}", "git_tags_url": "https://api.github.com/repos/sigmavirus24/github3.py/git/ tags{/sha}", "git_refs_url": "https://api.github.com/repos/sigmavirus24/github3.py/git/refs{/sha}", "trees_url": "https://api.github.com/ repos/sigmavirus24/github3.py/git/trees{/sha}", "statuses_url": "https://api.github.com/repos/sigmavirus24/github3.py/statuses/{sha}", "languages_url": "https://api.github.com/repos/sigmavirus24/github3.py/languages", "stargazers_url": "https://api.github.com/repos/ sigmavirus24/github3.py/stargazers", "contributors_url": "https://api.github.com/repos/sigmavirus24/github3.py/contributors", "subscribers_url": "https://api.github.com/repos/sigmavirus24/github3.py/subscribers", "subscription_url": "https://api.github.com/repos/ sigmavirus24/github3.py/subscription", "commits_url": "https://api.github.com/repos/sigmavirus24/github3.py/commits{/sha}", "git_commits_url": "https://api.github.com/repos/sigmavirus24/github3.py/git/commits{/sha}", "comments_url": "https://api.github.com/repos/ sigmavirus24/github3.py/comments{/number}", "issue_comment_url": "https://api.github.com/repos/sigmavirus24/github3.py/issues/comments/ {number}", "contents_url": "https://api.github.com/repos/sigmavirus24/github3.py/contents/{+path}", "compare_url": "https://api.github.com/ repos/sigmavirus24/github3.py/compare/{base}...{head}", "merges_url": "https://api.github.com/repos/sigmavirus24/github3.py/merges", "archive_url": "https://api.github.com/repos/sigmavirus24/github3.py/{archive_format}{/ref}", "downloads_url": "https://api.github.com/ repos/sigmavirus24/github3.py/downloads", "issues_url": "https://api.github.com/repos/sigmavirus24/github3.py/issues{/number}", "pulls_url": "https://api.github.com/repos/sigmavirus24/github3.py/pulls{/number}", "milestones_url": "https://api.github.com/repos/ sigmavirus24/github3.py/milestones{/number}", "notifications_url": "https://api.github.com/repos/sigmavirus24/github3.py/notifications{? since,all,participating}", "labels_url": "https://api.github.com/repos/sigmavirus24/github3.py/labels{/name}", "releases_url": "https:// api.github.com/repos/sigmavirus24/github3.py/releases{/id}", "created_at": "2012-03-13T19:58:53Z", "updated_at": "2015-01-15T08:07:34Z", "pushed_at": "2015-01-08T04:36:37Z", "git_url": "git://github.com/sigmavirus24/github3.py.git", "ssh_url": "git@github.com:sigmavirus24/ github3.py.git", "clone_url": "https://github.com/sigmavirus24/github3.py.git", "svn_url": "https://github.com/sigmavirus24/github3.py", "homepage": "http://github3py.readthedocs.org/", "size": 8669, "stargazers_count": 268, "watchers_count": 268, "language": "Python", "has_issues": true, "has_downloads": true, "has_wiki": false, "has_pages": true, "forks_count": 91, "mirror_url": null, "open_issues_count": 22, "forks": 91, "open_issues": 22, "watchers": 268, "default_branch": "develop", "network_count": 91, "subscribers_count": 24 } Gigantic Resources 37 www.rackspace.com
38. { "id": 3710711, "name": "github3.py", "full_name": "sigmavirus24/github3.py", "owner": { "login": "sigmavirus24", "id": 240830, "avatar_url": "https://avatars.githubusercontent.com/u/240830?v=3", "gravatar_id": "", "url": "https://api.github.com/users/sigmavirus24", "html_url": "https://github.com/sigmavirus24", "followers_url": "https://api.github.com/users/sigmavirus24/followers", "following_url": "https://api.github.com/users/sigmavirus24/following{/other_user}", "gists_url": "https://api.github.com/users/sigmavirus24/gists{/ gist_id}", "starred_url": "https://api.github.com/users/sigmavirus24/starred{/owner}{/repo}", "subscriptions_url": "https://api.github.com/ users/sigmavirus24/subscriptions", "organizations_url": "https://api.github.com/users/sigmavirus24/orgs", "repos_url": "https:// api.github.com/users/sigmavirus24/repos", "events_url": "https://api.github.com/users/sigmavirus24/events{/privacy}", "received_events_url": "https://api.github.com/users/sigmavirus24/received_events", "type": "User", "site_admin": false }, "private": false, "html_url": "https://github.com/sigmavirus24/github3.py", "description": "Python library for interfacing with the GitHub APIv3", "fork": false, "url": "https://api.github.com/repos/sigmavirus24/github3.py", "forks_url": "https://api.github.com/repos/sigmavirus24/ github3.py/forks", "keys_url": "https://api.github.com/repos/sigmavirus24/github3.py/keys{/key_id}", "collaborators_url": "https:// api.github.com/repos/sigmavirus24/github3.py/collaborators{/collaborator}", "teams_url": "https://api.github.com/repos/sigmavirus24/ github3.py/teams", "hooks_url": "https://api.github.com/repos/sigmavirus24/github3.py/hooks", "issue_events_url": "https://api.github.com/ repos/sigmavirus24/github3.py/issues/events{/number}", "events_url": "https://api.github.com/repos/sigmavirus24/github3.py/events", "assignees_url": "https://api.github.com/repos/sigmavirus24/github3.py/assignees{/user}", "branches_url": "https://api.github.com/repos/ sigmavirus24/github3.py/branches{/branch}", "tags_url": "https://api.github.com/repos/sigmavirus24/github3.py/tags", "blobs_url": "https:// api.github.com/repos/sigmavirus24/github3.py/git/blobs{/sha}", "git_tags_url": "https://api.github.com/repos/sigmavirus24/github3.py/git/ tags{/sha}", "git_refs_url": "https://api.github.com/repos/sigmavirus24/github3.py/git/refs{/sha}", "trees_url": "https://api.github.com/ repos/sigmavirus24/github3.py/git/trees{/sha}", "statuses_url": "https://api.github.com/repos/sigmavirus24/github3.py/statuses/{sha}", "languages_url": "https://api.github.com/repos/sigmavirus24/github3.py/languages", "stargazers_url": "https://api.github.com/repos/ sigmavirus24/github3.py/stargazers", "contributors_url": "https://api.github.com/repos/sigmavirus24/github3.py/contributors", "subscribers_url": "https://api.github.com/repos/sigmavirus24/github3.py/subscribers", "subscription_url": "https://api.github.com/repos/ sigmavirus24/github3.py/subscription", "commits_url": "https://api.github.com/repos/sigmavirus24/github3.py/commits{/sha}", "git_commits_url": "https://api.github.com/repos/sigmavirus24/github3.py/git/commits{/sha}", "comments_url": "https://api.github.com/repos/ sigmavirus24/github3.py/comments{/number}", "issue_comment_url": "https://api.github.com/repos/sigmavirus24/github3.py/issues/comments/ {number}", "contents_url": "https://api.github.com/repos/sigmavirus24/github3.py/contents/{+path}", "compare_url": "https://api.github.com/ repos/sigmavirus24/github3.py/compare/{base}...{head}", "merges_url": "https://api.github.com/repos/sigmavirus24/github3.py/merges", "archive_url": "https://api.github.com/repos/sigmavirus24/github3.py/{archive_format}{/ref}", "downloads_url": "https://api.github.com/ repos/sigmavirus24/github3.py/downloads", "issues_url": "https://api.github.com/repos/sigmavirus24/github3.py/issues{/number}", "pulls_url": "https://api.github.com/repos/sigmavirus24/github3.py/pulls{/number}", "milestones_url": "https://api.github.com/repos/ sigmavirus24/github3.py/milestones{/number}", "notifications_url": "https://api.github.com/repos/sigmavirus24/github3.py/notifications{? since,all,participating}", "labels_url": "https://api.github.com/repos/sigmavirus24/github3.py/labels{/name}", "releases_url": "https:// api.github.com/repos/sigmavirus24/github3.py/releases{/id}", "created_at": "2012-03-13T19:58:53Z", "updated_at": "2015-01-15T08:07:34Z", "pushed_at": "2015-01-08T04:36:37Z", "git_url": "git://github.com/sigmavirus24/github3.py.git", "ssh_url": "git@github.com:sigmavirus24/ github3.py.git", "clone_url": "https://github.com/sigmavirus24/github3.py.git", "svn_url": "https://github.com/sigmavirus24/github3.py", "homepage": "http://github3py.readthedocs.org/", "size": 8669, "stargazers_count": 268, "watchers_count": 268, "language": "Python", "has_issues": true, "has_downloads": true, "has_wiki": false, "has_pages": true, "forks_count": 91, "mirror_url": null, "open_issues_count": 22, "forks": 91, "open_issues": 22, "watchers": 268, "default_branch": "develop", "network_count": 91, "subscribers_count": 24 } Gigantic Resources 38 www.rackspace.com
39. Using mock 39 www.rackspace.com
40. mocked_session = mock.MagicMock() my_module.get_resource(mocked_session, ‘/users’) mocked_session.get.assert_called_once_with( ‘https://api.github.com/users’, params=None, headers=None ) Mocking Birds 40 www.rackspace.com
41. mocked_session = mock.MagicMock() my_module.get_resource(mocked_session, ‘/users’) mocked_session.get.assert_called_once_with( ‘https://api.github.com/users’, params=None, headers=None ) Mocking Birds 41 www.rackspace.com
42. mocked_session = mock.MagicMock() my_module.get_resource(mocked_session, ‘/users’) mocked_session.get.assert_called_once_with( ‘https://api.github.com/users’, params=None, headers=None ) Mocking Birds 42 www.rackspace.com
43. Approach the second 43 www.rackspace.com
44. session = requests.Session() response = get_resource(session, ‘/users’) assert response.ok Live Integration 44 www.rackspace.com
45. session = requests.Session() response = get_resource(session, ‘/users’) assert response.ok Live Integration 45 www.rackspace.com Now write and run 500 more of these
46. session = requests.Session() response = get_resource(session, ‘/users’) assert response.ok Live Integration 46 www.rackspace.com Now write and run 500 more of these
47. ......FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF Giant Bucket of FFFFFFFFFFFFFFFFFFFFFFFFFFFail 47 www.rackspace.com
48. Approach the third 48 www.rackspace.com
49. • vcr.py • betamax Available Libraries 49 www.rackspace.com
50. • vcr.py • betamax Available Libraries 50 www.rackspace.com
51. session = requests.Session() with vcr.use_cassette(‘vcrexample.yml’): resp = my_module.get_resource( session, ‘/users’) assert response.ok users = resp.json() assert len(users) > 0 Example with vcr.py 51 www.rackspace.com
52. session = requests.Session() with vcr.use_cassette(‘vcrexample.yml’): resp = my_module.get_resource( session, ‘/users’) assert response.ok users = resp.json() assert len(users) > 0 Example with vcr.py 52 www.rackspace.com
53. session = requests.Session() with vcr.use_cassette(‘vcrexample.yml’): resp = my_module.get_resource( session, ‘/users’) assert response.ok users = resp.json() assert len(users) > 0 Example with vcr.py 53 www.rackspace.com
54. session = requests.Session() recorder = betamax.Betamax( session, cassette_library_dir=‘.’) with recorder.use_cassette(‘betamaex’): resp = my_module.get_resource( session, ‘/users’) assert response.ok users = resp.json() assert len(users) > 0 Example with betamax 54 www.rackspace.com
55. Example with betamax 55 www.rackspace.com session = requests.Session() recorder = betamax.Betamax( session, cassette_library_dir=‘.’) with recorder.use_cassette(‘betamaex’): resp = my_module.get_resource( session, ‘/users’) assert response.ok users = resp.json() assert len(users) > 0
56. Example with betamax 56 www.rackspace.com session = requests.Session() recorder = betamax.Betamax( session, cassette_library_dir=‘.’) with recorder.use_cassette(‘betamaex’): resp = my_module.get_resource( session, ‘/users’) assert response.ok users = resp.json() assert len(users) > 0
57. Example with betamax 57 www.rackspace.com session = requests.Session() recorder = betamax.Betamax( session, cassette_library_dir=‘.’) with recorder.use_cassette(‘betamaex’): resp = my_module.get_resource( session, ‘/users’) assert response.ok users = resp.json() assert len(users) > 0
58. Reality 58 www.rackspace.com
59. Reality 59 www.rackspace.com
60. Reality 60 www.rackspace.com
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