Cope with 'Content-Length' value being a string (try-except)

Side benefits of this PR:
* makes tests compatible with python 2.7.0-2.7.8 (pin httpretty no higher than 0.9.4)
* makes tests compatible with httpretty 0.9.3 (as ckan uses, so this is handy for a developer using the same venv) ('content-length': None)

datapusher/jobs.py

@@ -360,10 +360,13 @@ def push_to_datastore(task_id, input, dry_run=False):
         response.raise_for_status()
 
         cl = response.headers.get('content-length')
-        if cl and int(cl) > MAX_CONTENT_LENGTH:
-            raise util.JobError(
-                'Resource too large to download: {cl} > max ({max_cl}).'
-                .format(cl=cl, max_cl=MAX_CONTENT_LENGTH))
+        try:
+            if cl and int(cl) > MAX_CONTENT_LENGTH:
+                raise util.JobError(
+                    'Resource too large to download: {cl} > max ({max_cl}).'
+                    .format(cl=cl, max_cl=MAX_CONTENT_LENGTH))
+        except ValueError:
+            pass
 
         tmp = tempfile.TemporaryFile()
         length = 0

requirements-dev.txt

@@ -1,3 +1,3 @@
 -r requirements.txt
-httpretty>=0.6
+httpretty==0.9.4
 nose==1.2.1

tests/test_acceptance.py

@@ -106,7 +106,7 @@ def register_urls(self, filename='simple.csv', format='CSV',
     @httpretty.activate
     @raises(util.JobError)
     def test_too_large_content_length(self):
-        """It should raise JobError if the returned Content-Length header 
+        """It should raise JobError if the returned Content-Length header
         is too large.
 
         If the returned header is larger than MAX_CONTENT_LENGTH then the async
@@ -169,7 +169,32 @@ def test_too_large_file(self):
             body='a' * size,
             content_type='application/json',
             forcing_headers={
-                'content-length': ''
+                'content-length': None
+            })
+
+        jobs.push_to_datastore('fake_id', data, True)
+
+    @httpretty.activate
+    def test_content_length_string(self):
+        """If the Content-Length header value is a string, just ignore it.
+        """
+        self.register_urls()
+        data = {
+            'api_key': self.api_key,
+            'job_type': 'push_to_datastore',
+            'metadata': {
+                'ckan_url': 'http://%s/' % self.host,
+                'resource_id': self.resource_id
+            }
+        }
+
+        source_url = 'http://www.source.org/static/file'
+        httpretty.register_uri(
+            httpretty.GET, source_url,
+            body='aaaaa',
+            content_type='application/json',
+            forcing_headers={
+                'Content-Length': 'some string'
             })
 
         jobs.push_to_datastore('fake_id', data, True)