Upgrade pytest to 3.6.0

https://github.com/pytest-dev/pytest/issues/1875 made it impossible to declare
a function as a fixture multiple times, which we were doing across different
modules. The fix was to move our @pytest.fixture calls into decorators in the
tests/fixtures.py module.

setup.py

@@ -48,7 +48,7 @@ setup(
     ''',
     setup_requires=['pytest-runner'],
     tests_require=[
-        'pytest==3.2.1',
+        'pytest==3.6.0',
         'aiohttp==2.3.2',
         'beautifulsoup4==4.6.0',
     ],

tests/fixtures.py

@@ -1,6 +1,7 @@
 from datasette.app import Datasette
 import itertools
 import os
+import pytest
 import random
 import sqlite3
 import sys
@@ -9,6 +10,7 @@ import tempfile
 import time
 
 
+@pytest.fixture(scope='session')
 def app_client(sql_time_limit_ms=None, max_returned_rows=None, config=None):
     with tempfile.TemporaryDirectory() as tmpdir:
         filepath = os.path.join(tmpdir, 'test_tables.db')
@@ -39,11 +41,13 @@ def app_client(sql_time_limit_ms=None, max_returned_rows=None, config=None):
         yield client
 
 
+@pytest.fixture(scope='session')
 def app_client_shorter_time_limit():
     yield from app_client(20)
 
 
-def app_client_returend_rows_matches_page_size():
+@pytest.fixture(scope='session')
+def app_client_returned_rows_matches_page_size():
     yield from app_client(max_returned_rows=50)
 
 

tests/test_api.py

@@ -1,7 +1,7 @@
-from .fixtures import (
+from .fixtures import ( # noqa
     app_client,
     app_client_shorter_time_limit,
-    app_client_returend_rows_matches_page_size,
+    app_client_returned_rows_matches_page_size,
     generate_compound_rows,
     generate_sortable_rows,
     METADATA,
@@ -9,10 +9,6 @@ from .fixtures import (
 import pytest
 import urllib
 
-pytest.fixture(scope='session')(app_client)
-pytest.fixture(scope='session')(app_client_shorter_time_limit)
-pytest.fixture(scope='session')(app_client_returend_rows_matches_page_size)
-
 
 def test_homepage(app_client):
     _, response = app_client.get('/.json')
@@ -936,11 +932,11 @@ def test_config_json(app_client):
     } == response.json
 
 
-def test_page_size_matching_max_returned_rows(app_client_returend_rows_matches_page_size):
+def test_page_size_matching_max_returned_rows(app_client_returned_rows_matches_page_size):
     fetched = []
     path = '/test_tables/no_primary_key.json'
     while path:
-        response = app_client_returend_rows_matches_page_size.get(
+        response = app_client_returned_rows_matches_page_size.get(
             path, gather_request=False
         )
         fetched.extend(response.json['rows'])

tests/test_html.py

@@ -1,12 +1,12 @@
 from bs4 import BeautifulSoup as Soup
-from .fixtures import app_client, app_client_shorter_time_limit
+from .fixtures import ( # noqa
+    app_client,
+    app_client_shorter_time_limit,
+)
 import pytest
 import re
 import urllib.parse
 
-pytest.fixture(scope='session')(app_client)
-pytest.fixture(scope='session')(app_client_shorter_time_limit)
-
 
 def test_homepage(app_client):
     response = app_client.get('/', gather_request=False)

tests/test_plugins.py

@@ -1,11 +1,9 @@
 from bs4 import BeautifulSoup as Soup
-from .fixtures import (
+from .fixtures import ( # noqa
     app_client,
 )
 import pytest
 
-pytest.fixture(scope='session')(app_client)
-
 
 def test_plugins_dir_plugin(app_client):
     response = app_client.get(