First test for conditional requests

Involves lots of mocking. Part of the issue is that there is no way (?) to
know where repo.json is stored when blender isn't running the show.

blenderpack.py

@@ -21,7 +21,37 @@ SCHEMA_VERSION = 1
 class BadAddon(Exception):
     pass
 
-def fetch(url, pipe):
+
+# TODO add repolist class
+
+def load_repo(url):
+    """
+    Searches local repo.json for repository with a matching 'url' and returns it
+    """
+    pass #TODO
+
+def write_repo(repo):
+    """
+    Writes repo to local repolist json
+    """
+    pass #TODO
+
+def fetch_repo(url: str) -> dict:
+    """ Requests repo.json from URL and embeds etag/last-modification headers"""
+    local_copy = load_repo(url)
+    headers = {}
+    if 'etag' in local_copy: headers['If-None-Match'] = local_copy['etag']
+    if 'last-modified' in local_copy: headers['If-Modified-Since'] = local_copy['last-modified']
+
+    resp = requests.get(url, headers=headers)
+
+    repo = json.loads(resp.json())
+    repo['etag'] = resp.headers.get('etag')
+    repo['last-modified'] = resp.headers.get('last-modified')
+
+    write_repo(repo)
+
+def refresh(url):
     # we have to explicitly close the end of the pipe we are NOT using,
     # otherwise no exception will be generated when the other process closes its end.
     pipe[0].close()
@@ -30,18 +60,8 @@ def fetch(url, pipe):
     local_repo_path.mkdir(exist_ok=True)
 
     try:
-        # TODO: do conditional request
-        re = requests.get(url)
-
+        fetch_repojson(url)
         pipe[1].send(re.status_code)
-
-        repo = re.json()
-        repo['etag'] = re.headers.get('etag')
-        repo['last-modified'] = re.headers.get('last-modified')
-
-        # just stick it here for now..
-        dump_repo(local_repo_path, repo)
-
     finally:
         pipe[1].close()
 

tests/test_refresh_repos.py

@@ -0,0 +1,72 @@
+import requests
+import unittest
+from unittest import mock
+from blenderpack import fetch_repo, load_repo, write_repo
+from datetime import datetime
+import json
+
+# based on https://stackoverflow.com/a/28507806/2730823
+
+# This method will be used by the mock to replace requests.get
+def mocked_requests_get(*args, **kwargs):
+    cidict = requests.structures.CaseInsensitiveDict
+    req_headers = cidict(kwargs.get('headers'))
+    t_fmt = '%a, %m %b %Y %X %Z'
+
+    class MockResponse:
+        def __init__(self, headers: cidict, status_code: int):
+            self.headers = headers
+            self.status_code = status_code
+
+        def json(self):
+            return json.dumps({'url': 'http://someurl.tld/repo.json'})
+
+    if args[0] == 'http://someurl.tld/repo.json':
+        resp_headers = cidict({
+            "ETag": '"2a0094b-b74-55326ced274f3"',
+            "Last-Modified": 'Sun, 13 Mar 2011 13:38:53 GMT',
+        })
+
+        if req_headers == {}:
+            resp_code = 200
+        else:
+            req_headers = cidict(req_headers)
+            resp_code = 304 if req_headers.get('if-none-match', '') == resp_headers['etag']\
+                        or datetime.strptime(req_headers.get('if-modified-since', ''), t_fmt) < \
+                           datetime.strptime(resp_headers['last-modified'], t_fmt) \
+                        else 200
+        return MockResponse(resp_headers, resp_code)
+
+    return MockResponse(None, 404)
+
+_mocked_repo_storage = {}
+def mocked_load_repo(*args, **kwargs):
+    global _mocked_repo_storage
+    if args[0] not in _mocked_repo_storage:
+        _mocked_repo_storage[args[0]] = {'url': args[0]}
+
+    return _mocked_repo_storage[args[0]]
+
+def mocked_write_repo(*args, **kwargs):
+    global _mocked_repo_storage
+    _mocked_repo_storage[args[0]['url']] = args[0]
+
+
+class fetch_url_twice(unittest.TestCase):
+
+    @mock.patch('requests.get', side_effect=mocked_requests_get)
+    @mock.patch('blenderpack.load_repo', side_effect=mocked_load_repo)
+    @mock.patch('blenderpack.write_repo', side_effect=mocked_write_repo)
+    def test_fetch(self, mock_write, mock_load, mock_get):
+        fetch_repo('http://someurl.tld/repo.json')
+        mock_get.assert_called_with('http://someurl.tld/repo.json', headers={})
+
+        fetch_repo('http://someurl.tld/repo.json')
+        mock_get.assert_called_with('http://someurl.tld/repo.json', headers={
+            'If-None-Match': '"2a0094b-b74-55326ced274f3"',
+            'If-Modified-Since': 'Sun, 13 Mar 2011 13:38:53 GMT'
+            })
+
+
+if __name__ == '__main__':
+    unittest.main()