diff --git a/pineappl_py/tests/test_bin.py b/pineappl_py/tests/test_bin.py
index 6c5c683c..5f32a993 100644
--- a/pineappl_py/tests/test_bin.py
+++ b/pineappl_py/tests/test_bin.py
@@ -1,6 +1,5 @@
 import numpy as np
 import pytest
-
 from pineappl.bin import BinRemapper
 
 
diff --git a/pineappl_py/tests/test_evolution.py b/pineappl_py/tests/test_evolution.py
index 51435bb0..4a296280 100644
--- a/pineappl_py/tests/test_evolution.py
+++ b/pineappl_py/tests/test_evolution.py
@@ -5,14 +5,14 @@
 """
 
 import itertools
-import numpy as np
 
-from pineappl.pids import PidBasis
+import numpy as np
 from pineappl.boc import Channel, Kinematics
-from pineappl.grid import Order, Grid
 from pineappl.convolutions import Conv, ConvType
-from pineappl.interpolation import Interp
 from pineappl.evolution import OperatorSliceInfo
+from pineappl.grid import Grid, Order
+from pineappl.interpolation import Interp
+from pineappl.pids import PidBasis
 
 
 class TestFkTable:
diff --git a/pineappl_py/tests/test_fk_table.py b/pineappl_py/tests/test_fk_table.py
index 5508c522..1f9781df 100644
--- a/pineappl_py/tests/test_fk_table.py
+++ b/pineappl_py/tests/test_fk_table.py
@@ -5,14 +5,13 @@
 """
 
 import numpy as np
-
-from pineappl.pids import PidBasis
 from pineappl.boc import Channel, Kinematics
-from pineappl.grid import Order, Grid
 from pineappl.convolutions import Conv, ConvType
-from pineappl.interpolation import Interp
 from pineappl.fk_table import FkTable
+from pineappl.grid import Grid, Order
 from pineappl.import_subgrid import ImportSubgridV1
+from pineappl.interpolation import Interp
+from pineappl.pids import PidBasis
 
 
 class TestFkTable:
diff --git a/pineappl_py/tests/test_grid.py b/pineappl_py/tests/test_grid.py
index 4132cccf..ee42b758 100644
--- a/pineappl_py/tests/test_grid.py
+++ b/pineappl_py/tests/test_grid.py
@@ -1,14 +1,12 @@
 import numpy as np
 import pytest
-
-from pineappl.pids import PidBasis
-from pineappl.boc import Channel, Kinematics
 from pineappl.bin import BinRemapper
-from pineappl.grid import Order, Grid
+from pineappl.boc import Channel, Kinematics
 from pineappl.convolutions import Conv, ConvType
-from pineappl.interpolation import Interp
+from pineappl.grid import Grid, Order
 from pineappl.import_subgrid import ImportSubgridV1
-
+from pineappl.interpolation import Interp
+from pineappl.pids import PidBasis
 
 # Construct the type of convolutions and the convolution object
 # We assume unpolarized proton PDF
diff --git a/pineappl_py/tests/test_subgrid.py b/pineappl_py/tests/test_subgrid.py
index 09e17f6a..c560499a 100644
--- a/pineappl_py/tests/test_subgrid.py
+++ b/pineappl_py/tests/test_subgrid.py
@@ -1,14 +1,12 @@
-import pytest
 import numpy as np
-
-from pineappl.pids import PidBasis
-from pineappl.boc import Channel, Order, Kinematics
+import pytest
+from pineappl.boc import Channel, Kinematics, Order
 from pineappl.convolutions import Conv, ConvType
 from pineappl.grid import Grid
+from pineappl.import_subgrid import ImportSubgridV1
 from pineappl.interpolation import Interp
+from pineappl.pids import PidBasis
 from pineappl.subgrid import SubgridEnum
-from pineappl.import_subgrid import ImportSubgridV1
-
 
 # Define some default for the minimum value of `Q2`
 Q2_MIN = 1e2