tests: Use 'pytest_sessionstart'

This is the recommended way to do pre-session configuration in pytest if
not using session fixtures [1].

With this, we're able to remove the custom 'test/run.py' script in its
entirety and run 'pytest' like everyone else does. We'll do this
separately to keep things simple.

[1] https://stackoverflow.com/a/12600154/613428

Signed-off-by: Stephen Finucane <stephen@that.guru>

tests/conftest.py

@@ -8,7 +8,9 @@
 """
 
 import os
+import shutil
 import sys
+import warnings
 
 import pytest
 from sphinx.testing.path import path
@@ -31,3 +33,32 @@ def rootdir():
 def pytest_report_header(config):
     return 'Running Sphinx test suite (with Python %s)...' % (
         sys.version.split()[0])
+
+
+def _filter_warnings():
+    def ignore(**kwargs): warnings.filterwarnings('ignore', **kwargs)
+
+    ignore(category=DeprecationWarning, module='site')  # virtualenv
+    ignore(category=PendingDeprecationWarning, module=r'_pytest\..*')
+    ignore(category=ImportWarning, module='backports')
+    ignore(category=ImportWarning, module='pkgutil')
+    ignore(category=ImportWarning, module='pytest_cov')
+
+
+def _initialize_test_directory(session):
+    testroot = os.path.join(str(session.config.rootdir), 'tests')
+    tempdir = os.path.abspath(os.getenv('SPHINX_TEST_TEMPDIR',
+                              os.path.join(testroot, 'build')))
+    os.environ['SPHINX_TEST_TEMPDIR'] = tempdir
+
+    print('Temporary files will be placed in %s.' % tempdir)
+
+    if os.path.exists(tempdir):
+        shutil.rmtree(tempdir)
+
+    os.makedirs(tempdir)
+
+
+def pytest_sessionstart(session):
+    _filter_warnings()
+    _initialize_test_directory(session)

tests/run.py

@@ -9,35 +9,8 @@
     :copyright: Copyright 2007-2017 by the Sphinx team, see AUTHORS.
     :license: BSD, see LICENSE for details.
 """
-from __future__ import print_function
-
-import os
 import sys
-import warnings
-import traceback
-import shutil
 
-testroot = os.path.dirname(__file__) or '.'
+import pytest
-sys.path.insert(0, os.path.abspath(os.path.join(testroot, os.path.pardir)))
 
-# filter warnings of test dependencies
-warnings.filterwarnings('ignore', category=DeprecationWarning, module='site')  # virtualenv
-warnings.filterwarnings('ignore', category=ImportWarning, module='backports')
-warnings.filterwarnings('ignore', category=ImportWarning, module='pkgutil')
-warnings.filterwarnings('ignore', category=ImportWarning, module='pytest_cov')
-warnings.filterwarnings('ignore', category=PendingDeprecationWarning, module=r'_pytest\..*')
-
-# find a temp dir for testing and clean it up now
-os.environ['SPHINX_TEST_TEMPDIR'] = \
-    os.path.abspath(os.path.join(testroot, 'build')) \
-    if 'SPHINX_TEST_TEMPDIR' not in os.environ \
-    else os.path.abspath(os.environ['SPHINX_TEST_TEMPDIR'])
-
-tempdir = os.environ['SPHINX_TEST_TEMPDIR']
-print('Temporary files will be placed in %s.' % tempdir)
-if os.path.exists(tempdir):
-    shutil.rmtree(tempdir)
-os.makedirs(tempdir)
-
-import pytest  # NOQA
 sys.exit(pytest.main(sys.argv[1:]))