maint(precommit): Apply isort (#3195)

* Apply isort

* Tweak isort config

* Add env.py as a known_first_party

* Add one missing known first party

* Make config compat with older isort versions

* Add another comment

* Revert pyproject setting

tests/test_copy_move.py

 # -*- coding: utf-8 -*-
 import pytest
+
 from pybind11_tests import copy_move_policies as m
 
 

tests/test_custom_type_casters.py

 # -*- coding: utf-8 -*-
 import pytest
+
 from pybind11_tests import custom_type_casters as m
 
 

tests/test_eigen.py

 # -*- coding: utf-8 -*-
 import pytest
+
 from pybind11_tests import ConstructorStats
 
 np = pytest.importorskip("numpy")

tests/test_enum.py

 # -*- coding: utf-8 -*-
 import pytest
+
 from pybind11_tests import enums as m
 
 

tests/test_eval.py

@@ -4,7 +4,6 @@ import os
 import pytest
 
 import env  # noqa: F401
-
 from pybind11_tests import eval_ as m
 
 

tests/test_exceptions.py

@@ -4,9 +4,8 @@ import sys
 import pytest
 
 import env  # noqa: F401
-
-from pybind11_tests import exceptions as m
 import pybind11_cross_module_tests as cm
+from pybind11_tests import exceptions as m
 
 
 def test_std_exception(msg):

tests/test_factory_constructors.py

 # -*- coding: utf-8 -*-
-import pytest
 import re
 
-import env  # noqa: F401
+import pytest
 
+import env  # noqa: F401
+from pybind11_tests import ConstructorStats
 from pybind11_tests import factory_constructors as m
 from pybind11_tests.factory_constructors import tag
-from pybind11_tests import ConstructorStats
 
 
 def test_init_factory_basic():

tests/test_iostream.py

 # -*- coding: utf-8 -*-
-from pybind11_tests import iostream as m
 import sys
-
 from contextlib import contextmanager
 
+from pybind11_tests import iostream as m
+
 try:
     # Python 3
     from io import StringIO

tests/test_kwargs_and_defaults.py

@@ -2,7 +2,6 @@
 import pytest
 
 import env  # noqa: F401
-
 from pybind11_tests import kwargs_and_defaults as m
 
 

tests/test_local_bindings.py

@@ -2,7 +2,6 @@
 import pytest
 
 import env  # noqa: F401
-
 from pybind11_tests import local_bindings as m
 
 

tests/test_methods_and_attributes.py

@@ -2,9 +2,8 @@
 import pytest
 
 import env  # noqa: F401
-
-from pybind11_tests import methods_and_attributes as m
 from pybind11_tests import ConstructorStats
+from pybind11_tests import methods_and_attributes as m
 
 
 def test_methods_and_attributes():

tests/test_modules.py

 # -*- coding: utf-8 -*-
+from pybind11_tests import ConstructorStats
 from pybind11_tests import modules as m
 from pybind11_tests.modules import subsubmodule as ms
-from pybind11_tests import ConstructorStats
 
 
 def test_nested_modules():
@@ -54,18 +54,20 @@ def test_reference_internal():
 
 
 def test_importing():
-    from pybind11_tests.modules import OD
     from collections import OrderedDict
 
+    from pybind11_tests.modules import OD
+
     assert OD is OrderedDict
     assert str(OD([(1, "a"), (2, "b")])) == "OrderedDict([(1, 'a'), (2, 'b')])"
 
 
 def test_pydoc():
     """Pydoc needs to be able to provide help() for everything inside a pybind11 module"""
-    import pybind11_tests
     import pydoc
 
+    import pybind11_tests
+
     assert pybind11_tests.__name__ == "pybind11_tests"
     assert pybind11_tests.__doc__ == "pybind11 test module"
     assert pydoc.text.docmodule(pybind11_tests)

tests/test_multiple_inheritance.py

@@ -2,7 +2,6 @@
 import pytest
 
 import env  # noqa: F401
-
 from pybind11_tests import ConstructorStats
 from pybind11_tests import multiple_inheritance as m
 

tests/test_numpy_array.py

@@ -2,7 +2,6 @@
 import pytest
 
 import env  # noqa: F401
-
 from pybind11_tests import numpy_array as m
 
 np = pytest.importorskip("numpy")

tests/test_numpy_dtypes.py

@@ -4,7 +4,6 @@ import re
 import pytest
 
 import env  # noqa: F401
-
 from pybind11_tests import numpy_dtypes as m
 
 np = pytest.importorskip("numpy")

tests/test_numpy_vectorize.py

 # -*- coding: utf-8 -*-
 import pytest
+
 from pybind11_tests import numpy_vectorize as m
 
 np = pytest.importorskip("numpy")

tests/test_opaque_types.py

 # -*- coding: utf-8 -*-
 import pytest
-from pybind11_tests import opaque_types as m
+
 from pybind11_tests import ConstructorStats, UserType
+from pybind11_tests import opaque_types as m
 
 
 def test_string_list():

tests/test_operator_overloading.py

 # -*- coding: utf-8 -*-
 import pytest
-from pybind11_tests import operators as m
+
 from pybind11_tests import ConstructorStats
+from pybind11_tests import operators as m
 
 
 def test_operator_overloading():

tests/test_pickling.py

@@ -2,7 +2,6 @@
 import pytest
 
 import env  # noqa: F401
-
 from pybind11_tests import pickling as m
 
 try:

tests/test_pytypes.py

 # -*- coding: utf-8 -*-
 from __future__ import division
-import pytest
+
 import sys
 
-import env  # noqa: F401
+import pytest
 
-from pybind11_tests import pytypes as m
+import env  # noqa: F401
 from pybind11_tests import debug_enabled
+from pybind11_tests import pytypes as m
 
 
 def test_int(doc):