Mock urlopen to make tests more robust

conda.recipe/meta.yaml

@@ -38,6 +38,7 @@ test:
     - pytables >=3.0.0
     - sqlalchemy >=0.8.0
     - bcolz
+    - mock
     - pymongo >=2.8,<3 # [not (py35 or win)]
     - dask
     - paramiko # [not win]

etc/requirements_ci.txt

@@ -17,6 +17,7 @@ Jinja2==2.8
 jmespath==0.9.0
 locket==0.2.0
 MarkupSafe==0.23
+mock==2.0.0
 msgpack-python==0.4.8
 multipledispatch==0.4.9
 networkx==1.11

odo/backends/tests/test_url.py

@@ -1,6 +1,7 @@
 from __future__ import print_function
 
 import pytest
+from mock import patch, Mock
 
 from functools import partial
 import codecs
@@ -64,8 +65,10 @@ def test_sample_different_encoding():
 
 
 @pytest.mark.xfail(raises=HTTPError)
-def test_failed_url():
+@patch('odo.backends.url.urlopen')
+def test_failed_url(m):
     failed_url = "http://foo.com/myfile.csv"
+    m.side_effect = HTTPError(failed_url, 404, 'Not found', None, None)
     with tmpfile('.csv') as fn:
         odo(failed_url, fn)