diff --git a/pandas/tests/arithmetic/conftest.py b/pandas/tests/arithmetic/conftest.py
index 44e6cc664de6dd..671fe69750c57a 100644
--- a/pandas/tests/arithmetic/conftest.py
+++ b/pandas/tests/arithmetic/conftest.py
@@ -1,16 +1,16 @@
 # -*- coding: utf-8 -*-
-import pytest
-
 import numpy as np
-import pandas as pd
+import pytest
 
 from pandas.compat import long
-import pandas.util.testing as tm
 
+import pandas as pd
+import pandas.util.testing as tm
 
 # ------------------------------------------------------------------
 # Helper Functions
 
+
 def id_func(x):
     if isinstance(x, tuple):
         assert len(x) == 2
diff --git a/pandas/tests/arithmetic/test_datetime64.py b/pandas/tests/arithmetic/test_datetime64.py
index f20d9a54e9da32..f97a1651163e86 100644
--- a/pandas/tests/arithmetic/test_datetime64.py
+++ b/pandas/tests/arithmetic/test_datetime64.py
@@ -2,29 +2,26 @@
 # Arithmetic tests for DataFrame/Series/Index/Array classes that should
 # behave identically.
 # Specifically for datetime64 and datetime64tz dtypes
-import operator
 from datetime import datetime, timedelta
-import warnings
 from itertools import product, starmap
+import operator
+import warnings
 
 import numpy as np
 import pytest
 import pytz
 
-import pandas as pd
-import pandas.util.testing as tm
-
-from pandas.compat.numpy import np_datetime64_compat
-from pandas.errors import PerformanceWarning, NullFrequencyError
-
 from pandas._libs.tslibs.conversion import localize_pydatetime
 from pandas._libs.tslibs.offsets import shift_months
+from pandas.compat.numpy import np_datetime64_compat
+from pandas.errors import NullFrequencyError, PerformanceWarning
 
-from pandas.core.indexes.datetimes import _to_M8
-
+import pandas as pd
 from pandas import (
-    Timestamp, Timedelta, Period, Series, date_range, NaT,
-    DatetimeIndex, TimedeltaIndex)
+    DatetimeIndex, NaT, Period, Series, Timedelta, TimedeltaIndex, Timestamp,
+    date_range)
+from pandas.core.indexes.datetimes import _to_M8
+import pandas.util.testing as tm
 
 
 def assert_all(obj):
diff --git a/pandas/tests/arithmetic/test_numeric.py b/pandas/tests/arithmetic/test_numeric.py
index c603485f6f076d..7afb90978131d5 100644
--- a/pandas/tests/arithmetic/test_numeric.py
+++ b/pandas/tests/arithmetic/test_numeric.py
@@ -6,20 +6,20 @@
 from itertools import combinations
 import operator
 
-import pytest
 import numpy as np
-
-import pandas as pd
-import pandas.util.testing as tm
+import pytest
 
 from pandas.compat import PY3, Iterable
-from pandas.core import ops
-from pandas import Timedelta, Series, Index, TimedeltaIndex
 
+import pandas as pd
+from pandas import Index, Series, Timedelta, TimedeltaIndex
+from pandas.core import ops
+import pandas.util.testing as tm
 
 # ------------------------------------------------------------------
 # Comparisons
 
+
 class TestNumericComparisons(object):
     def test_operator_series_comparison_zerorank(self):
         # GH#13006
diff --git a/pandas/tests/arithmetic/test_object.py b/pandas/tests/arithmetic/test_object.py
index e9a3f4accc4865..9917c45ef6d120 100644
--- a/pandas/tests/arithmetic/test_object.py
+++ b/pandas/tests/arithmetic/test_object.py
@@ -4,19 +4,18 @@
 # Specifically for object dtype
 import operator
 
-import pytest
 import numpy as np
+import pytest
 
 import pandas as pd
-import pandas.util.testing as tm
-from pandas.core import ops
-
 from pandas import Series, Timestamp
-
+from pandas.core import ops
+import pandas.util.testing as tm
 
 # ------------------------------------------------------------------
 # Comparisons
 
+
 class TestObjectComparisons(object):
 
     def test_comparison_object_numeric_nas(self):
diff --git a/pandas/tests/arithmetic/test_period.py b/pandas/tests/arithmetic/test_period.py
index 469353042a878f..cdacd4b42d6831 100644
--- a/pandas/tests/arithmetic/test_period.py
+++ b/pandas/tests/arithmetic/test_period.py
@@ -7,20 +7,20 @@
 import numpy as np
 import pytest
 
-import pandas as pd
-import pandas.util.testing as tm
-
 from pandas._libs.tslibs.period import IncompatibleFrequency
 from pandas.errors import PerformanceWarning
 
+import pandas as pd
+from pandas import Period, PeriodIndex, Series, period_range
 from pandas.core import ops
-from pandas import Period, PeriodIndex, period_range, Series
-from pandas.tseries.frequencies import to_offset
+import pandas.util.testing as tm
 
+from pandas.tseries.frequencies import to_offset
 
 # ------------------------------------------------------------------
 # Comparisons
 
+
 class TestPeriodIndexComparisons(object):
 
     @pytest.mark.parametrize("other", ["2017", 2017])
diff --git a/pandas/tests/arithmetic/test_timedelta64.py b/pandas/tests/arithmetic/test_timedelta64.py
index 12ed174d6cc53a..4474b06b195361 100644
--- a/pandas/tests/arithmetic/test_timedelta64.py
+++ b/pandas/tests/arithmetic/test_timedelta64.py
@@ -3,17 +3,16 @@
 # behave identically.
 from datetime import datetime, timedelta
 
-import pytest
 import numpy as np
-
-import pandas as pd
-import pandas.util.testing as tm
+import pytest
 
 from pandas.errors import NullFrequencyError, PerformanceWarning
+
+import pandas as pd
 from pandas import (
-    timedelta_range,
-    Timedelta, Timestamp, NaT, Series, TimedeltaIndex, DatetimeIndex,
-    DataFrame)
+    DataFrame, DatetimeIndex, NaT, Series, Timedelta, TimedeltaIndex,
+    Timestamp, timedelta_range)
+import pandas.util.testing as tm
 
 
 def get_upcast_box(box, vector):
diff --git a/setup.cfg b/setup.cfg
index c21f09f131dbd0..a1c82304c5a72e 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -121,12 +121,6 @@ skip=
     pandas/tests/api/test_types.py,
     pandas/tests/api/test_api.py,
     pandas/tests/tools/test_numeric.py,
-    pandas/tests/arithmetic/test_numeric.py,
-    pandas/tests/arithmetic/test_object.py,
-    pandas/tests/arithmetic/test_period.py,
-    pandas/tests/arithmetic/test_datetime64.py,
-    pandas/tests/arithmetic/conftest.py,
-    pandas/tests/arithmetic/test_timedelta64.py,
     pandas/tests/internals/test_internals.py,
     pandas/tests/plotting/test_datetimelike.py,
     pandas/tests/plotting/test_series.py,