Make sessions REST API test more robust.

Was seeing failures on Windows because it failed to delete the folder.

IPython/html/services/sessions/tests/test_sessions_api.py

@@ -1,107 +1,114 b''
 """Test the sessions web service API."""
 
+import errno
 import io
 import os
 import json
 import requests
 import shutil
 
 pjoin = os.path.join
 
 from IPython.html.utils import url_path_join
 from IPython.html.tests.launchnotebook import NotebookTestBase, assert_http_error
 from IPython.nbformat.current import new_notebook, write
 
 class SessionAPI(object):
     """Wrapper for notebook API calls."""
     def __init__(self, base_url):
         self.base_url = base_url
 
     def _req(self, verb, path, body=None):
         response = requests.request(verb,
                 url_path_join(self.base_url, 'api/sessions', path), data=body)
 
         if 400 <= response.status_code < 600:
             try:
                 response.reason = response.json()['message']
             except:
                 pass
         response.raise_for_status()
 
         return response
 
     def list(self):
         return self._req('GET', '')
 
     def get(self, id):
         return self._req('GET', id)
 
     def create(self, name, path):
         body = json.dumps({'notebook': {'name':name, 'path':path}})
         return self._req('POST', '', body)
 
     def modify(self, id, name, path):
         body = json.dumps({'notebook': {'name':name, 'path':path}})
         return self._req('PATCH', id, body)
 
     def delete(self, id):
         return self._req('DELETE', id)
 
 class SessionAPITest(NotebookTestBase):
     """Test the sessions web service API"""
     def setUp(self):
         nbdir = self.notebook_dir.name
+        try:
         os.mkdir(pjoin(nbdir, 'foo'))
+        except OSError as e:
+            # Deleting the folder in an earlier test may have failed
+            if e.errno != errno.EEXIST:
+                raise
 
         with io.open(pjoin(nbdir, 'foo', 'nb1.ipynb'), 'w') as f:
             nb = new_notebook(name='nb1')
             write(nb, f, format='ipynb')
 
         self.sess_api = SessionAPI(self.base_url())
 
     def tearDown(self):
         for session in self.sess_api.list().json():
             self.sess_api.delete(session['id'])
-        shutil.rmtree(pjoin(self.notebook_dir.name, 'foo'))
+        shutil.rmtree(pjoin(self.notebook_dir.name, 'foo'),
+                      ignore_errors=True)
 
     def test_create(self):
         sessions = self.sess_api.list().json()
         self.assertEqual(len(sessions), 0)
 
         resp = self.sess_api.create('nb1.ipynb', 'foo')
         self.assertEqual(resp.status_code, 201)
         newsession = resp.json()
         self.assertIn('id', newsession)
         self.assertEqual(newsession['notebook']['name'], 'nb1.ipynb')
         self.assertEqual(newsession['notebook']['path'], 'foo')
         self.assertEqual(resp.headers['Location'], '/api/sessions/{0}'.format(newsession['id']))
 
         sessions = self.sess_api.list().json()
         self.assertEqual(sessions, [newsession])
 
         # Retrieve it
         sid = newsession['id']
         got = self.sess_api.get(sid).json()
         self.assertEqual(got, newsession)
 
     def test_delete(self):
         newsession = self.sess_api.create('nb1.ipynb', 'foo').json()
         sid = newsession['id']
 
         resp = self.sess_api.delete(sid)
         self.assertEqual(resp.status_code, 204)
 
         sessions = self.sess_api.list().json()
         self.assertEqual(sessions, [])
 
         with assert_http_error(404):
             self.sess_api.get(sid)
 
     def test_modify(self):
         newsession = self.sess_api.create('nb1.ipynb', 'foo').json()
         sid = newsession['id']
 
         changed = self.sess_api.modify(sid, 'nb2.ipynb', '').json()
         self.assertEqual(changed['id'], sid)
         self.assertEqual(changed['notebook']['name'], 'nb2.ipynb')
         self.assertEqual(changed['notebook']['path'], '')