Fix bug when thumbnail representations are not found

boxsdk/object/file.py

@@ -771,7 +771,7 @@ def get_thumbnail_representation(self, dimensions, extension='png'):
         Retrieve a thumbnail image for the file.
 
         :param dimensions:
-            The width by height size of this representation in pixels (i.e. '92x92')
+            The width by height size of this representation in pixels (e.g. '92x92')
         :type dimensions:
             `unicode`
         :param extension:
@@ -785,10 +785,12 @@ def get_thumbnail_representation(self, dimensions, extension='png'):
         """
         rep_hints = '[{0}?dimensions={1}]'.format(extension, dimensions)
         representation = self.get_representation_info(rep_hints)
-        url = representation[0]['content']['url_template']
-        url = url.replace('{+asset_path}', '')
-        response = self._session.get(url, expect_json_response=False)
-        return response.content
+        if len(representation):
+            url = representation[0]['content']['url_template']
+            url = url.replace('{+asset_path}', '')
+            response = self._session.get(url, expect_json_response=False)
+            return response.content
+        return b''
 
     @api_call
     def copy(self, parent_folder, name=None, file_version=None):

test/unit/object/test_file.py

@@ -868,3 +868,37 @@ def test_get_thumbnail_representation(
                                          params={'fields': 'representations'})
     mock_box_session.get.assert_any_call(content_url, expect_json_response=False)
     assert thumb == mock_content_response.content
+
+
+def test_get_thumbnail_representation_not_found(
+        test_file,
+        mock_box_session,
+        mock_content_response,
+):
+    representation_url = '{0}/files/{1}'.format(API.BASE_API_URL, test_file.object_id)
+    dimensions = '100x100'
+    extension = 'jpg'
+
+    mock_representations_response = Mock()
+    mock_representations_response.json.return_value = {
+        'etag': '1',
+        'id': test_file.object_id,
+        'representations': {
+            'entries': [],
+        },
+        'type': 'file'
+    }
+
+    mock_box_session.get.side_effect = [mock_representations_response, mock_content_response]
+
+    thumb = test_file.get_thumbnail_representation(
+        dimensions=dimensions,
+        extension=extension,
+    )
+
+    mock_box_session.get.assert_any_call(
+        representation_url,
+        headers={'X-Rep-Hints': '[{}?dimensions={}]'.format(extension, dimensions)},
+        params={'fields': 'representations'},
+    )
+    assert b'' == thumb