Work around circular import

Author: blueyed

src/_pytest/compat.py

@@ -1,12 +1,18 @@
 """
 python version compatibility code
 """
+import sys  # isort:skip
+
+if sys.version_info < (3, 5, 2):
+    from typing_extensions import TYPE_CHECKING
+else:
+    from typing import TYPE_CHECKING
+
 import functools
 import inspect
 import io
 import os
 import re
-import sys
 from contextlib import contextmanager
 from inspect import Parameter
 from inspect import signature
@@ -28,10 +34,6 @@
 from _pytest.outcomes import fail
 from _pytest.outcomes import TEST_OUTCOME
 
-if sys.version_info < (3, 5, 2):
-    from typing_extensions import TYPE_CHECKING
-else:
-    from typing import TYPE_CHECKING
 
 if TYPE_CHECKING:
     from typing import Type  # noqa: F401 (used in type string)

tox.ini

@@ -182,6 +182,8 @@ markers =
 [flake8]
 max-line-length = 120
 extend-ignore = E203
+per-file-ignores =
+  src/_pytest/compat.py: E402
 
 [isort]
 ; This config mimics what reorder-python-imports does.